Congenital eye diseases in humans. Hereditary eye diseases. Alternative treatment of glaucoma
Hereditary diseases of the organ of vision are a large group of genetically heterogeneous diseases with a severe course, leading to early disability.
Genetics (from the Greek "genesis" - birth, origin), put forward in the category of exact sciences, shows that heredity is due to the transfer to descendants of repeating information about all the properties of a given organism. One of the important properties of heredity is conservatism, that is, the preservation of hereditary characteristics over many generations. Molecular biology shows broad prospects for altering the hereditary nature of an organism, which makes it possible to introduce or remove certain genes. This area of genetics is called "genetic engineering".
Currently, the study of new approaches based on the combined study of the clinical signs of the disease and their correlation with the results of genetic analysis is the basis for the development of promising methods for the prevention and treatment of a number of congenital and genetically determined diseases of the organ of vision. Intrafamilial and pronounced interpopulation clinical polymorphism of diseases of the visual-nerve apparatus was established, which indicates their different genetic nature.
In the monograph Khlebnikova O.V. and Dadali E.L. "Hereditary pathology of the organ of vision", published under the editorship of E.K. Ginter, published modern ideas about the etiology, clinic, diagnosis and new opportunities for the prevention of hereditary eye diseases. Based on their own data on clinical and genetic correlations, the authors developed algorithms for DNA diagnosis of the most severe forms of hereditary eye diseases, presented an atlas of the clinical forms of the latter and their index by signs that allow practicing ophthalmologists to suggest or establish the clinical and genetic form of the disease. As a result of population epidemiological studies, the authors found that in different regions of the Russian Federation, hereditary etiology is detected in 30% of patients with eye diseases, and in the structure of blindness and low vision it ranges from 42 to 84% in various populations. According to A.M. Shamshinova (2001), in 42.3% of cases eye diseases are caused by hereditary factors. In recent years, there has been a clear trend towards an increase in the proportion of hereditary diseases in the structure of ophthalmopathology.
For practical ophthalmologists, the identification of a genetic variant is necessary not only to determine the characteristics of clinical manifestations and the course of an eye disease, but, first of all, to establish the type of inheritance, calculate the risk of having a sick child in a burdened family, and plan preventive measures aimed at preventing his birth. DNA diagnostic methods are more accurate than traditional methods, as they allow you to assess the genetic risk of developing an eye disease in the family. To date, insufficient work has been done to identify individual genetic variants using molecular genetic methods. Unfortunately, there are not enough such research centers in the country. And the existing laboratory for DNA diagnostics and the laboratory for genetic epidemiology at the Moscow State Scientific Center of the Russian Academy of Medical Sciences cannot cover a large contingent of those who need these examinations.
It is important to remember the terminology related to hereditary pathology. Gene - the basic unit of heredity, is embodied in the substance of heredity - deoxyribonucleic acid (DNA) and is a section of its molecule that is transmitted from parents to their descendants. The sizes of genes are not the same and depend on the size of the protein that encodes a given gene. There are over 20,000 genes.
Epigenetics - the science of gene activity and its change, studies everything related to DNA and affecting its structure and function. It is well known that the hereditary nature of an organism is determined by a set of genes (genome) contained in the DNA of each cell. DNA contains more than 3 billion nucleotide bases of four main types: adenine, cytosine, guanine and thymine. A large amount of DNA is stored in a relatively small volume of the cell nucleus. Each chromosome contains one strand of DNA. The sequence of bases in DNA determines the life of a person.
The cause of hereditary diseases is damage to the genes that are part of the cell - a unique biological structural unit of the body. The nucleus of each cell contains chromosomes - the material carriers of human hereditary properties, containing one giant DNA molecule and hundreds of thousands of genes that control important links in the exchange at all stages of the development of the human body. Therefore, the most direct approach to diagnosing hereditary diseases is to study the DNA of the relevant genes. Modern methods of molecular genetics make it possible to study virtually any DNA fragment of a human cell. A necessary condition for conducting DNA diagnostics is the availability of information about the location of the gene on a particular chromosome. Locus - a separate section of the chromosome responsible for the implementation of a certain hereditary trait.
Genome - a set of chromosomes containing units of heredity. Therefore, the hereditary nature of an organism is determined by the genome contained in the DNA of each cell. Through mapping, it is possible to identify the position of each gene on any chromosome relative to other genes.
The gene creates enzymes that regulate biochemical processes and ensures the vital activity of the cell. DNA methylation is an important biochemical pathway, the violation of which leads to the development of eye diseases. As a result of the most complex biochemical changes in the body under the influence of many causes (diseases, intoxication, environmental influences, low and high temperatures, ionizing radiation, etc.), a change in the structure of chromosomes and genes - mutations can occur. A mutation in a human somatic or germ cell can lead to the development of a hereditary disease: corneal dystrophy, hereditary cataract, congenital glaucoma, retinal abiotrophy, and many others.
The most important problem in the practice of counseling is to determine the type of inheritance of the disease. Three main types of inheritance have been proven: 1) autosomal recessive type - both parents are carriers of the defective gene, the pathological gene is passed from generation to generation, the incidence of the disease in men and women is the same (example: cystic fibrosis); 2) autosomal dominant type - only one of the parents can be a carrier of the gene (example: tuberculous scleritis); 3) X-linked inheritance is characterized by the following genealogical data: a sick father can pass on a pathological gene to daughters who are phenotypically healthy, but are carriers of a defective chromosome. A carrier woman can receive a pathological gene from both mother and father and passes it on to her sons (example: congenital color vision deficiency).
In the Ufa Research Institute of Eye Diseases, together with the Institute of Biochemistry and Genetics of the Ufa Scientific Center of the Russian Academy of Sciences, molecular genetic studies of certain hereditary diseases of the organ of vision have been carried out for many years.
For the first time in the Republic of Bashkortostan, the effectiveness of predicting congenital hereditary cataracts was studied, taking into account genetic factors and its surgical treatment. The linkage of the autosomal dominant congenital cataract gene with highly polymorphic microsatellite markers located within the β-crystallin gene cluster was analyzed. The genotyping of individuals of the studied pedigrees by marker loci was carried out and the genetic heterogeneity of autosomal dominant congenital cataract was studied. The possibility of prenatal diagnosis of congenital hereditary cataract based on the established linkage of the ADVC gene with microsatellite markers D22S264, TOP1P2, CRYBB2 in the region of the β-crystallin gene cluster has been proven. The lack of linkage of autosomal dominant congenital cataract with the above markers in a number of other families with this pathology indicates its genetic heterogeneity.
In the children's department of the institute, genetic studies were carried out on the problem of pigment abiotrophy (Greek bios - life, trophe - nutrition) of the retina in adults and children. Tapeto-retinal abiotrophies in children are among the poorly studied severe hereditary progressive diseases that lead to blindness at working age. The disease is inherited in an autosomal recessive manner. According to the type of inheritance, monogenic (caused by defects in one gene) and digenic (caused by defects in two genes) retinal pigment abiotrophy are distinguished.
The recurrence of this pathology in families in the 3rd-4th generation was revealed, more often manifested in children with a close relationship of their parents. Several clinical forms of retinitis pigmentosa have been identified. The degree of development of retinal pigmentation depends on the genetic type of retinitis pigmentosa and the age of the patient. Various periods of manifestation of new signs of the disease were noted - from 8-10 years to 40-55 years. With the disease, a violation of dark adaptation, a concentric narrowing of the visual fields, and night blindness are noted. Various forms of hereditary retinal degeneration are caused by the manifestation of a mutation in the rhodopsin gene. Perinatal diagnosis is assisted by molecular biological genotyping, which makes it possible to identify a large number of genes that cause this disease. However, at present, interaction between practicing ophthalmologists and specialists in the field of molecular genetics is far from always carried out.
The Institute conducted research on hereditary open-angle glaucoma. Based on a clinical, genealogical and molecular genetic study of members of 138 families, it was found that in patients with aggravated heredity, the predominant clinical form of primary open-angle glaucoma is pseudoexfoliative glaucoma (56.8%), and in the group without aggravated heredity - pigmentary glaucoma (45.5 %). A clinical and genealogical study of families in which primary open-angle glaucoma was confirmed in several generations revealed the similarity of the clinical manifestations of the disease, and the phenomenon of anticipation was traced. As a result of molecular genetic analysis, it was found that the frequency of the Q368X mutation of the myocilin gene in the group with aggravated heredity is 1.35%, which indicates the advisability of testing it in people with a family history of the disease. Therefore, if there is a family history of primary open-angle glaucoma, its premorbid diagnosis in blood relatives is necessary.
Single-digit comparisons were made between husband and wife, parents and children. A higher correlation coefficient between parents and offspring compared with those between spouses testified to the great importance of genotypic factors in determining traits. The summation of hereditary signs and micro-features, the identification of patterns of their impact on the development of glaucoma in representatives of a particular pedigree made it possible to diagnose the disease or predisposition to it in a timely manner. Tests for susceptibility to glaucoma, as noted by R.P. Shikunova help predict the disease long before its clinical manifestations and contribute to the correct prediction of pathology in future generations.
To date, the clinical and genetic characteristics of 20 nosological forms of hereditary corneal dystrophies, represented by 35 genetic variants, have been well studied. Autosomal dominant, autosomal recessive, and X-linked recessive inheritance patterns of IRR have been described. Hereditary diseases of the cornea are represented by dystrophies of various layers of the cornea and ectasias. In recent years, cases of keratoconus have become more frequent, most of which are sporadic. Only in 6-8% of cases, the monogenic nature of the disease was established. Five clinically indistinguishable genetic variants of keratoconus have been described, and the keratoconus gene has been mapped on the chromosome. Research at the institute on the problem of inheritance of keratoconus continues.
Thus, the identification of a pathological gene and its mutations is the basis for understanding the pathogenesis of the disease, predicting the course of the process, and searching for effective therapy. Given the existence of an extensive nosological spectrum and pronounced genetic heterogeneity of hereditary diseases of the organ of vision, systematic work is needed to determine the algorithm for clinical genetic research in burdened families.
Clinical genetics. E.F. Davydenkova, I.S. Lieberman. Leningrad. "The medicine". 1976
LEADING SPECIALISTS IN THE FIELD OF GENETICS
Amelina Svetlana Sergeevna - Professor of the Department of Genetics and Laboratory Genetics, Doctor of Medical Sciences. Doctor geneticist of the highest qualification category
Degtereva Elena Valentinovna - assistant of the department in the course of genetics and laboratory genetics, geneticist of the first category
Page editor: Oksana Kryuchkova
The eye has long been one of the favorite objects of observation in medical genetics. Its accessible position, the ability to dynamically monitor the state of its external parts, media and fundus, the relatively good knowledge of the structure of the eye tissues, the brightness of the clinical manifestations of most ophthalmic diseases make it easier to study the hereditary pathology of the eye than the pathology of any other organ.
Large studies in ophthalmogenetics have been carried out by Nettleship, Bell, Uscher, Franceschetti, Waardenburg, Francois and others.
In our country, due to the complete elimination of some infectious eye diseases and a sharp decrease in others, the proportion of congenital and hereditary eye defects has significantly increased. So, according to our data, among 154 schoolchildren blind from birth in Leningrad, 36 had a hereditary disease.
The works of S. A. Barkhash, S. N. Gorkova, O. A. Panteleeva, E. I. Starodubtseva, N. S. Eremenko and others speak of the great importance of hereditary pathology of the eyes. consulting with our ophthalmologists is still small.
The material in this chapter is arranged according to the principle adopted in most eye manuals. Inheritance of eye changes in diseases of other systems and organs is discussed in the relevant chapters.
ANOMALIES OF REFRACTION
The question of the inheritance of clinical refraction has been studied for a long time. The ratio of environmental factors and heredity in the development of refraction of the eye still causes controversy. Studying refraction in 50 pairs of twins, we were convinced that the coincidence of refraction in single-zygote twins was in 30 pairs out of 32, and among two-zygotic twins - only in 4 pairs out of 18 (G. M. Chutko et al., 1971).
The complexity of the issues of inheritance of refraction is clearly visible when considering views on myopia - an anomaly of refraction, which is one of the most common causes of decreased vision and, from the genetic side, the most studied type of refraction.
Already at the beginning of the XIX century. oculists observed that myopia often occurs in many members of the same family, and spoke in favor of the hereditary origin of myopia.
The concept of predisposition to myopia was introduced. J What predisposition does a person have even before his birth. Under the influence of environmental factors, it leads to an anomaly of refraction. The predisposition is inherited.
In 1913 Steiger wrote that myopia is a hereditary condition. Steiger pointed out that refraction depends on the length of the axis of the eye and on its refractive power. But he believed that the relationships between these factors are purely random. As always happens, when, ignoring the integrity and complexity of the problem, they are erected in absolutely only one side of it, his followers lost sight of the other side - the influence of the external environment.
Determining the type of inheritance of myopia causes difficulties due to the different manifestations of hereditary predisposition. An important question is whether one or more genes are involved in the development of predisposition to myopia, i.e. whether monogenic or polygenic inheritance takes place. Probably, one should think about the polygenic conditionality of myopia.
D. I. Berezinskaya (1925) believed that myopia is inherited as a monogenic recessive; she cites the results of a survey of children born in a marriage between myopes and persons with a different refraction, and children born from a marriage between myopes. She finds that the results of the study prove the recessive inheritance of myopia.
A. A. Kholina (192e) considered myopia to be a recessively inherited trait, “depending on at least two, to a certain extent, independently Mendelian inclinations (genes).” In accordance with this opinion, there are at least 2 genetically different forms of myopia.
Wold (1949) notes that there can be both a paratypical form of myopia and hereditary myopia (moreover, inherited both recessively and dominantly).
P. A. Andogsky (1930) considered the cause of hereditary myopia to be the transmission of “thinness and compliance of the eye wall”, the hereditary conditionality of deep orbits.
E. Zh. Tron (1947) wrote that myopia is heterogeneous in origin; he divided myopia into school and progressive, considering the first to be a biological variant closely related to inheritance. E. Zh. Tron noted that optical elements are subject to mutual influence during the development of the organism, which contributes to the approach of refraction in most people to emmetropia.
E. S. Avetisov (1967) writes that "the role of heredity in various forms of myopia and in different individuals is not the same."
According to A. A. Malinovsky (1970), myopia, in contrast to a number of monogenically transmitted lesions of the organ of vision
it is polygenically determined, and the hereditary predisposition to myopia manifests itself with different expressivity under the influence of environmental factors. Therefore, it is important to identify the most threatened contingents early and apply extensive preventive measures.
Farsightedness (hypermetropia) is usually congenital. In the genetic aspect, it has been studied less than myopia. Citing pedigrees of individuals with high hypermetropia, many researchers consider the most common type of autosomal recessive inheritance.
Waardenburg (1961, 1963) considered that a dominant transmission of this refractive error is also possible.
High hypermetropia is often one of the symptoms of microphthalmos, flat and small cornea, aphakia and other diseases accompanied by a violation of the proportionality of the refractive power of the optical system and the length of the eye axis.
Everything said about farsightedness and myopia applies to astigmatism. It should be emphasized that we often see not only the same degree of astigmatism in different generations, but also the coincidence of the main axes of astigmatism in parents and descendants.
STRABISMUS
Concomitant strabismus is the result of a disorder of binocular vision, mainly due to refractive errors.
A significant role of heredity in strabismus is noted by many authors. E. M. Fisher (1958) wrote that there are many cases when parents or close relatives of a squinting child have strabismus. Pratt-Johnson and Lunn (1967) found in 65% hereditary conditionality of concomitant strabismus. However, E. M. Fisher emphasizes that the inheritance of refractive errors, as well as a weakened desire for binocular vision, leads to strabismus.
N. I. Pilman (1964) criticized the position expressed by some experts: if one of the family members once had strabismus, which subsequently spontaneously disappeared, then in subsequent generations it will disappear on its own. N. I. Pilman believes that such a “self-healed” person does not have binocular vision, that the doctor should not wait for self-healing, but should actively treat a mowing child.
In our practice, we sometimes met with dominantly inherited accommodative strabismus. However, our experience does not yet allow us to conclude that the prognosis is the same for different family members. Each patient has to be treated according to an individual plan.
Most experts consider the main type of inheritance of strabismus dominant. The recessive type of inheritance is much less common. It is probably correct to consider the inheritance of strabismus as polygenic.
CONGENITAL DISORDERS OF COLOR PERCEPTION
Congenital color blindness is a common eye deficiency. According to domestic sources, the frequency of congenital color vision disorders among men is on average 8%, and among women - 0.5%.
Among the various forms of color vision disorders, blindness to red or green color (protanopia and deuteranopia) is most common. This color blindness is inherited from the grandfather to the grandson born from the daughter. This pattern of inheritance of the disease was called the Iiorner-Nasse law (but named after Horner, who formulated it for color vision impairment, and Nasse, who formulated it for hemophilia).
Genes affecting the appearance of color vision disorders and other sex-related diseases are localized on the X chromosome; the gene for normal color vision is dominant in relation to the recessive gene for impaired color perception (Table 19).
It is believed that every sixth woman is a conductor - a carrier of the gene for color blindness. Interestingly, among women suffering from Shereshevsky-Turner disease (they have only one X chromosome), color blindness is much more common than usual. This is well illustrated by the pedigree described by Lenz (1957). In this pedigree, two brothers are color blind, their sister is probably a conductor. From the marriage of this woman with a flowering man, a color-blind son and daughter were born. The fact that the son is color-blind is easily explained. The daughter would not have had this anomaly if she had two X chromosomes. But the daughter had Shereshevsky-Turner disease, that is, she had only one X chromosome (carrier of the color blindness gene), treated from her mother, in connection with this, color blindness manifested itself.
Regarding the inheritance of a rare form of congenital color blindness to purple (tritanopia), there is no data yet.
Some authors believe that complete color blindness (monochromacy) may be inherited, but the type of inheritance has not been established. Other authors question the fact that color blindness is inherited by all three colors.
A rare congenital disease "achromatopia" is characterized by the absence of color perception for all colors (monochromasia), amblyopia, nystagmus, photophobia, nyctopia, central scotoma, astigmatism. Often the disease is combined with atro
optic nerve disease, retinitis pigmentosa, retinitis albescens, or macular degeneration.
TABLE 19 Hereditary transmission of color perception disorders
E. E. Somov in 1963 described this disease in a brother and sister.
CHANGES IN THE EYELIDS AND TLAILARITIES
Ankyloblepharon. Ankyloblepharon is a congenital pathology in which the edges of the eyelids are fused together for some distance, as a result of which the palpebral fissure is shortened. This pathology can also be in the form of jumpers dividing the palpebral fissure in half.
The etiology of this disease is unknown. A significant role is played by heredity. The disease is inherited in a dominant manner. Fine (1933) gave his observation in which a mother and two sons were affected, Fiolho (1929) described ankyloblepharon in a man, in 3 of his 9 sons and 1 granddaughter; familial cases are also described by Ashley (1947) et al.
Epicanthus. Epicanthus - a lunate fold of skin that covers the inner commissure of the eyelids. Epicanthus is often found in representatives of the Mongolian race. It is believed that it is present in all children in utero, but in most newborns of the European race, the epicanthus disappears by the time of birth or later as the back of the nose grows. Epicanthus can be inherited by dominant type. Numerous works indicate just such a transfer of this feature.
Epicanthus is a common symptom in embryopathies and many hereditary diseases of the body (for example, in chromosomal diseases).
congenital ptosis. There are simple congenital ptosis associated with levator palsy, and ptosis associated with other congenital somatic defects and defects of the nervous system.
The hereditary transmission of ptosis is well known. Numerous works are devoted to this issue. One of them describes a family in which 64 people out of 128 persons in 6 generations had ptosis. In this family, ptosis was dominantly transmitted.
Probably, each ophthalmologist has his own observations on families in which this anomaly is inherited. In one of the families we examined, bilateral congenital ptosis was transmitted in four generations according to the dominant type.
L. A. Dymshits (1970) noted that isolated ptosis is transmitted only dominantly, and in combination with epicanthus - both dominant and recessive.
Congenital blepharophimosis. The concept of "congenital blepharophimosis" usually includes three anomalies: ptosis, epicanthus, shortening of the palpebral fissure. This pathology is always bilateral, is congenital. Such patients have a peculiar appearance. They are very similar to each other, their head is usually thrown back up, and because of the narrowness and shortening of the palpebral fissure, it seems that they are constantly squinting. The disease does not respond well to surgical treatment. Sometimes other pathological changes (microphthalmos, microblepharon) are found in such patients.
The disease is more often sporadic, but can be inherited. Most authors believe that the form of inheritance of the disease is dominant. Dimitri (1922), who was the first to propose a name for this disease, cites a pedigree in which 21 out of 38 people in 5 generations suffered from blepharophimosis.
A. A. Akhmedzyanov and V. I. Nasyrova in 1965 published observations on a family in which congenital ptosis, epicanthus, and shortening of the palpebral fissures have been transmitted for 143 years. Of the 105 family members, 27 people inherited this anomaly. According to the authors' observation, females in whom an anomaly was found often suffered from menstrual irregularities and infertility. Assessing the given pedigree, this pathology should be attributed to diseases with a dominant type of inheritance.
We observed an 8-year-old girl suffering from blepharophimosis; the father and his son from another marriage suffered from the same disease; two other families also showed dominant transmission of the disease.
Blepharochalasis. This term refers to the drooping of the skin fold of the upper eyelid. Usually this disease is acquired, but congenital blepharochalasis also occurs. Congenital blepharochalasis is often hereditary, inherited in a dominant manner. Paimeton (1936) described a family in 3 generations of which 13 males and 38 females had this anomaly. Badtke (1961) also notes her in 3 generations.
Distichiasis. Distichiasis - double growth of eyelashes. With this congenital disease, eyelashes grow along both the anterior and posterior ribs of the eyelids. This anomaly is more often bilateral.
A large number of cases of inheritance of distichiasis have been described. Waardenburg (1963) believes that distichiasis is inherited in a dominant manner.
Congenital inversion of the eyelids. This pathology is not common, but there are already a sufficient number of descriptions of the dominant inheritance of such a disease.
Xanthelasma. Xanthelasmas are inherited in a dominant manner. Currently, xanthelasmas are considered skin manifestations of hypercholesterolemic and hyperlipemic xanthomatosis.
Dacryocystitis. In addition to numerous cases of dacryocystitis, which are caused by environmental factors and are well known to all ophthalmologists, there are also those in which dacryocystitis is hereditarily caused.
Many authors write about congenital dacryocystitis, observed in several family members, transmitted dominantly.
It is believed that congenital dacryocystitis in 9% of cases is hereditarily caused.
B. L. Polyak and F. A. Popova (1929) described hereditary dacryocystitis in two families. It is interesting to note that in one of the families, the disease in all three individuals began at the age of 25 years. The authors believe that in these families there was a pathology of the nose (flattening it, reducing the size of the shells), which was inherited and led to secondary inflammatory changes in the lacrimal sac.
The example of hereditary dacryocystitis in adults shows that a well-collected anamnesis can reveal the influence of heredity even in those diseases in which the possibility of inheritance is little known.
Dacryocystitis in newborns is not uncommon. In the literature, the question was raised whether the delay in the reverse development of the connective tissue membrane that closes the lacrimal ducts is, in some cases, hereditary. According to many pedigrees, neonatal dacryocystitis can be inherited in a dominant manner.
APLASIA AND DYSPLASIA OF THE EYEBALL
Microphthalmos. Microphthalmos (reducing the size of the eyeball) is a common congenital anomaly. Microphthalmos can be expressed in varying degrees. Sometimes the size of the eyeball is reduced so much that they even talk about incomplete anophthalmos. With microphthalmos, there is always a decrease in the size of the palpebral fissure and cornea. Microphthalmos without pathology of the lens and choroid is inherited in a recessive manner.
Parents of sick children are usually healthy. In many described cases of such microphthalmos, related marriages are noted among the parents of patients.
VP Efroimson (1968) indicates the possibility of inheritance of microphthalmos as a recessive, linked to the X chromosome.
If microphthalmos is associated with coloboma of the eyeball, i.e., with non-closure of the eyecup in the embryonic period of development, then the disease is inherited dominantly. In such cases, this pathology is usually combined with clouding of the corneas, cataracts, and other anomalies of the eye and the whole organism.
Anophthalmos. Anophthalmos is the absence of an eye. Congenital anophthalmos is called complete when, even with careful examination, no traces of the eyeball can be found in the orbit. Usually, both the optic nerve and the chiasm are absent. Often it is not possible to detect even the optical aperture of the orbit.
In cases where the disease is not a phenocopy, it is inherited in a recessive manner. In all cases described in the literature, the hereditary anophthalmos was bilateral, the consanguinity of the parents was noted.
It is necessary to carefully compare the aplasia and dysplasia of the eye with other malformations of the body, since there is a certain relationship between various combinations of anomalies and the types of inheritance of anophthalmos and microphthalmos.
In addition to genetic inheritance, microphthalmos and anophthalmos can be the result of chromosomal aberration (for example, in Patau syndrome).
Cryptophthalmos. Cryptophthalmos or ablepharia is a congenital malformation in which the palpebral fissure is absent, the skin of the forehead passes into the skin of the cheek without a break in the orbit. Often there are no structural elements of the eyelids. The eyeball with this anomaly is underdeveloped (microphthalmos or anophthalmos).
Cryptophthalmos can be combined with other malformations: clefts of the face, palate, lips, syndactyly, etc.
The disease is rare. L. A. Dymshits and E. M. Yufit (1960) note that only 30-40 cases of cryptophthalmos have been described.
L. A. Dymshits and E. M. Yufit give a pedigree in which a 3-year-old girl had bilateral cryptophthalmos, her older brother had left-sided cryptophthalmos (the other brother is healthy); both brothers of the girl's father also had cryptophthalmos (the older one had one-sided, the younger one had two-sided). The girl's parents had no pathological changes in the eyes. From this small pedigree, it is clear that a significant number of family members had cryptophthalmos in two generations. In our opinion, in the pedigree given by L. A. Dymshits and E. M. Yufit, cryptophthalmos was inherited dominantly with incomplete manifestation. Most other authors note that the disease is inherited recessively.
We saw one infant with bilateral cryptophthalmos, but we were unable to obtain any data on the presence of this defect in other family members; it was also not possible to connect the appearance of this defect with any disease of the mother during pregnancy. Thus, in our case, one can think either of the sporadic occurrence of a defect, or of its recessive inheritance.
The eyes are one of the most important organs for a person, associated with the brain and other organs. Based on the information given by the eyes, a person performs certain actions, orients himself in space, and forms the perception of actions and objects.
Some people, due to heredity, cannot use their eyesight to the fullest. Congenital eye anomalies occur in 1-2% of all newborns. Modern medicine has found more than 1200 genes responsible for the possibility of certain diseases.
Many of the hereditary eye diseases are asymptomatic, do not change visual acuity, so a person may not notice some small changes for a long time, and thereby loses precious time.
Types of hereditary eye diseases
Ophthalmologists divide hereditary diseases into 3 groups:
Among eye diseases that are inherited or that occur at the initial stage of fetal development, there are:
Glaucoma
Glaucoma- a severe chronic disease of the eye, which is characterized by increased intraocular pressure (IOP). In this case, the optic nerve is affected, vision is reduced and complete blindness is possible. The optic nerve completely dies, and blindness is irreversible.
Unfortunately, glaucoma is quite common, it affects people over the age of forty. According to WHO, the number of glaucoma patients in the world reaches 100 million people. At a younger age, glaucoma is much less common.
Intraocular pressure rises for two main reasons: the formation of an excessive amount of intraocular fluid and a violation of the excretion of intraocular fluid by the drainage system of the eye. The retention of intraocular fluid causes an increase in IOP, and high IOP leads to death of the optic nerve and blindness. However, what causes excessive fluid formation is still unknown. It is believed that hereditary factors play a huge role in the occurrence of glaucoma. If the family has relatives with glaucoma, it is necessary to undergo an examination by an ophthalmologist at least once a year.
Neglect of treatment for glaucoma inevitably leads to blindness.
There are several types of glaucoma:
congenital glaucoma. which can be caused by genetic causes or diseases and injuries of the fetus during periods of embryonic development or childbirth. Congenital glaucoma manifests itself in the first weeks of life. The disease is quite rare - there is only 1 case of glaucoma per 10-20 thousand newborns.
The cause of the disease is most often heredity of an autosomal recessive type. In this case, anomalies of the eyeball are observed. The causes may also be the effects on the fetus of diseases such as measles rubella . flu . toxoplasmosis . mumps . hypoxia .
Juvenile or juvenile glaucoma. It develops in children after three years and young people up to 35 years of age. The causes of the disease are congenital changes in the iris of the eye.
Secondary glaucoma- this is a consequence of other eye or general diseases in which the eye structures responsible for the circulation and outflow of intraocular fluid from the eye are affected. Causes can also be mechanical damage to the eye.
Primary glaucoma in adults- the most common type of chronic glaucoma, which is associated with age-related eye changes. The disease is divided into 4 main clinical forms: open-angle glaucoma. mixed glaucoma. angle-closure glaucoma and glaucoma with normal IOP .
Symptoms of glaucoma
Symptoms of glaucoma directly depend on the form and stage of development of the disease. Its insidiousness is that at the initial stage of the disease, 80% of patients do not experience any inconvenience. What should be alarming:
Congenital glaucoma in children is manifested by stretching of the cornea, which is elastic in newborns and returns to normal size after the first week of life. With glaucoma, the eyes appear more expressive and larger than normal. This leads to stretching and thinning of the retina and its further detachment with breaks.
Observed myopia or myopic astigmatism . a slight increase in intraocular pressure in the early stages of the disease. There is swelling of the cornea, which leads to deterioration of vision, and in the future it is associated with atrophy of the optic nerve and deformation of the fundus.
The main task in the treatment of glaucoma is to maintain visual functions with minimal side effects from the therapy used and to maintain a normal quality of life for the patient. The key to successful treatment is the correct understanding by the patient of the serious prognosis of the disease and the need for adequate treatment.
Treat glaucoma conservative(medical) method, laser and surgical way. Drug treatment, in turn, is carried out in three areas: ophthalmo-hypotensive therapy - measures aimed at reducing intraocular pressure. Measures aimed at improving the blood supply to the inner eye membranes and the intraocular part of the optic nerve. Normalization of metabolism (metabolic processes) in the eye tissues to influence the dystrophic processes that are characteristic of glaucoma. The symptoms of glaucoma and its complications are stopped.
Previously, pilocarpine, a drug that constricts the pupil of the eye, was used to treat glaucoma with drugs. Now he has been replaced by new drugs: Betoptic . Betadine . Timolol . Trusopt . Xalatan and a number of others. The latest drugs allow a more targeted effect on glaucoma: reduce fluid production and improve its outflow.
Laser treatment became possible not so long ago, after the creation of modern ophthalmic laser systems with a certain set of parameters that affect the structures of the eyeball. This made it possible to develop and apply a variety of methods for laser treatment of glaucoma.
Laser treatment of glaucoma has a number of advantages: firstly, low invasiveness of the procedure, secondly, the complete absence of serious complications that may occur in the postoperative period, thirdly, the possibility of treatment on an outpatient basis, which significantly affects the economy, the possibility of , if necessary, repeated laser interventions, with a significant decrease in the hypotensive effect in the postoperative period.
Laser treatment of glaucoma carried out according to the following methods:
Surgical treatment consists in creating an alternative system for the outflow of intraocular fluid, after which the intraocular pressure normalizes without the use of medications.
Different forms and types of glaucoma suggest different types of surgical intervention and are solved, each time, individually. An exception is congenital glaucoma in children, this form of the disease is treated only by surgical methods.
Prevention of glaucoma
Glaucoma is perhaps the most common cause of blindness, and therefore the prevention of disease progression is of great socio-economic importance for both the individual and society as a whole.
The course of the disease largely depends on the patient's lifestyle; glaucoma treatment cannot be successful without lifestyle modification. Physical and nervous overload should be avoided, especially at an older age. The permissible maximum weight for lifting should not exceed 10 kg. You should also not read in poor lighting and for a long period.
Of great importance is the diet, it is necessary to eat rationally, according to age. Preference should be given to vegetable dishes, fish, raw vegetables and fruits and limit the intake of animal fats and sugar. Nicotine is very harmful to the eyes, therefore, it is better to stop smoking, the sooner the better.
The most effective in the prevention of glaucoma is a systematic examination by an ophthalmologist and control of intraocular pressure, for people over 40-45 years old. You need to visit a doctor at least once a year. Particularly attentive to the prevention of glaucoma should be people who have relatives with glaucoma.
In the case when the first symptoms of glaucoma appear, you should immediately consult a doctor. If any form of glaucoma is detected, it is imperative to be under dispensary observation with an ophthalmologist. Remember that at present, medicine is not able to restore vision lost as a result of the progression of glaucoma.
congenital glaucoma
congenital glaucoma
Congenital glaucoma is a genetic, less often acquired in utero disease, which is characterized by underdevelopment of the angle of the anterior chamber of the eye and the trabecular meshwork, which ultimately leads to an increase in intraocular pressure. This condition is considered relatively rare in ophthalmology and occurs in approximately one case per 10,000 births. Some researchers believe that these statistics do not quite correctly reflect reality, because some forms of congenital glaucoma may not manifest themselves until adolescence. Despite the fact that the pathology is inherited by an autosomal recessive mechanism, boys are somewhat prevalent among patients - the sex distribution is approximately 3:2. According to the age of development of the main symptoms, as well as the presence or absence of genetic defects, several clinical forms of this disease are distinguished. The importance of timely detection of congenital glaucoma is due to the fact that without treatment, a child can go blind 4-5 years after the development of the first manifestations of the pathology.
Causes of congenital glaucoma
The vast majority of cases of congenital glaucoma (at least 80%) are accompanied by a mutation of the CYP1B1 gene, which is localized on the 2nd chromosome. It encodes the cytochrome P4501B1 protein, the functions of which have not been sufficiently studied to date. It is assumed that this protein is somehow involved in the synthesis and destruction of signaling molecules that are involved in the formation of the trabecular network of the anterior chamber of the eye. Defects in the structure of cytochrome P4501B1 lead to the fact that the metabolism of the above compounds becomes abnormal, which contributes to impaired eye formation and the development of congenital glaucoma. Now more than fifty varieties of CYP1B1 gene mutations are known that are reliably associated with the development of this disease, but it has not yet been possible to identify the relationship between specific gene defects and certain clinical forms.
In addition, there are indications of a role in the development of congenital glaucoma of another gene, MYOC, located on the 1st chromosome. Its expression product, a protein called myocillin, is widely distributed in eye tissues and is also involved in the formation and functioning of the trabecular meshwork of the eye. Mutations in this gene were previously known to be the cause of juvenile open-angle glaucoma. however, with simultaneous damage to MYOC and CYP1B1, a congenital version of this pathology develops. Some researchers in the field of genetics believe that the detection of a myocillin gene mutation on the background of a defect in CYP1B1 does not play a special clinical role in the development of congenital glaucoma and is simply a coincidence. Mutations in both of these genes are inherited in an autosomal recessive manner.
In addition to hereditary forms of this pathology, congenital glaucoma is diagnosed in approximately 20% of cases in the absence of both cases of the disease and pathological genes in parents. In this case, the cause of the development of eye disorders can be either spontaneous mutations or damage to the tissues of the eye in the prenatal period. The latter may be due to infection of the mother during pregnancy with certain infections (for example, toxoplasmosis, rubella), intrauterine fetal injuries, retinoblastoma. exposure to teratogenic factors. Since there is no genetic defect in this situation, this pathology is called secondary congenital glaucoma. In addition, similar disorders of the organ of vision can occur with some other congenital diseases (Marfan's syndrome, anhidrosis, and others).
Whatever the cause of congenital glaucoma, the mechanism for the development of disorders in this condition is almost the same. Due to the underdevelopment of the angle of the anterior chamber of the eye and the trabecular meshwork, aqueous humor cannot normally leave the cavity, it accumulates, which is accompanied by a gradual increase in intraocular pressure. A feature of congenital glaucoma is the fact that the tissues of the sclera and cornea in children have greater elasticity than in adults, therefore, with the accumulation of moisture, the size of the eyeball increases (most often two at once, very rarely only one). This somewhat reduces intraocular pressure, but over time, this mechanism becomes insufficient. There is a flattening of the lens and the cornea, the latter may appear micro-ruptures, leading to opacification; the optic disc is damaged, the retina becomes thinner. Ultimately, its detachment can occur - corneal clouding and retinal detachment are the leading causes of blindness in congenital glaucoma.
Classification of congenital glaucoma
In clinical practice, congenital glaucoma is primarily divided into three varieties - primary, secondary and combined. Primary is caused by genetic disorders, is inherited by an autosomal recessive mechanism and accounts for about 80% of all cases of the disease. The cause of secondary congenital glaucoma is an intrauterine disorder in the formation of the organs of vision of various non-genetic nature. The combined variety, as the name implies, is accompanied by the presence of congenital glaucoma against the background of other hereditary diseases and conditions. The primary form, due to genetic defects, in turn is divided into three clinical forms:
- Early congenital glaucoma - with this form, signs of the disease are detected at birth, or they appear in the first three years of a child's life.
- Infantile congenital glaucoma - develops at the age of 3-10 years, its clinical course has little resemblance to the early type and approaches that of adults with other forms of glaucoma.
- Juvenile congenital glaucoma - the first manifestations of this form of the disease are recorded most often in adolescence, the symptoms are very similar to the infantile type of pathology.
Such a significant spread in the age of development of congenital glaucoma is directly related to the degree of underdevelopment of the trabecular network of the eye. The more pronounced violations in these structures, the earlier begins the accumulation of aqueous humor with an increase in intraocular pressure. If the underdevelopment of the angle of the anterior chamber of the eye does not reach significant values, then in the first years of the child's life the outflow occurs quite normally, and the disturbances develop much later. Attempts to associate certain clinical forms of congenital glaucoma with specific types of CYP1B1 gene mutations have not been successful to date, and the mechanisms for the development of one or another type of disease are still unknown.
Symptoms of congenital glaucoma
The most peculiar manifestations are characterized by an early form of primary congenital glaucoma, which is due to the anatomical features of the structure of the eye in a child under the age of 3 years. In very rare cases, glaucoma changes can be noticed already at birth, most often in the first 2-3 months of life, the disease does not manifest itself. Then the child becomes restless, sleeps poorly, very often naughty - this is due to unpleasant and painful sensations, from which congenital glaucoma debuts. After a few weeks or months, a slow increase in the size of the eyeballs (rarely one) begins. An increase in intraocular pressure and elasticity of the sclera tissues can lead to a significant increase in the eyes, which outwardly creates a false impression of a beautiful "big-eyed" child. Then edema, photophobia, lacrimation join these symptoms, and sometimes there is clouding of the cornea.
Infantile and juvenile forms of congenital glaucoma are very similar in many respects, only the age of development of the first manifestations of the disease differs. An increase in the size of the eyeballs, as a rule, does not occur, the pathology begins with a feeling of discomfort and soreness in the eyes, headaches. The child may complain of a deterioration in vision (the appearance of bright halos around light sources, "midges" before the eyes). These types of congenital glaucoma are often accompanied by other disorders of the visual apparatus - strabismus. astigmatism. myopia. Over time, there is a narrowing of the field of view (the ability to see objects with peripheral vision is lost), a violation of dark adaptation. Photophobia, edema, and vascular injection of the sclera, characteristic of the early form of the disease, are most often not observed in these forms. Left untreated, any type of congenital glaucoma eventually leads to blindness due to retinal detachment or optic nerve atrophy.
Diagnosis of congenital glaucoma
The detection of congenital glaucoma is performed by an ophthalmologist on the basis of examination data, ophthalmological studies (tonometry, gonioscopy, keratometry, biomicroscopy, ophthalmoscopy, ultrasound biometry). Also, an important role in the diagnosis of this condition is played by genetic studies, the study of hereditary history and the course of pregnancy. On examination, enlarged (with an early form) or normal size of the eyes are found, swelling of the tissues surrounding the eyeball may also be observed. The horizontal diameter of the cornea is increased, microtears and clouding are possible on it, the sclera is thinned and has a bluish tint, it is affected in congenital glaucoma and the iris - atrophic processes occur in it, the pupil reacts sluggishly to light stimuli. The anterior chamber of the eye is deepened (1.5-2 times more than the age norm).
No pathological changes occur in the fundus for a long time, since due to an increase in the size of the eyeball, intraocular pressure at first does not reach significant values. But then the excavation of the optic disc develops quite quickly, however, with a decrease in pressure, the severity of this phenomenon also decreases. Due to the increase in the size of the eyes in congenital glaucoma, thinning of the retina occurs, which, if left untreated, can lead to its rupture and rhegmatogenous detachment. Often, against the background of such changes, myopia is detected. Tonometry shows a slight increase in intraocular pressure, but this indicator should be compared with the anterior-posterior size of the eye, since scleral stretching smooths out IOP.
The study of hereditary history can reveal similar changes in the patient's relatives, while it is often possible to determine the autosomal recessive type of inheritance - this indicates in favor of primary congenital glaucoma. The presence during pregnancy of infectious diseases of the mother, injuries, exposure to teratogenic factors indicates the possibility of developing a secondary form of the disease. Genetic diagnostics is carried out by direct sequencing of the CYP1B1 gene sequence, which makes it possible to identify its mutations. Thus, only a geneticist can unambiguously prove the presence of primary congenital glaucoma. In addition, in the presence of such a condition in one of the parents or their relatives, it is possible to search for the pathological form of the gene before conception or prenatal diagnosis by amniocentesis or other methods.
Treatment and prognosis of congenital glaucoma
Treatment of congenital glaucoma is only surgical, it is possible to use modern laser technologies. Conservative therapy using traditional agents (pilocarpine drops, clonidine, epinephrine, dorzolamide) is auxiliary and can be used for some time while waiting for the operation. Surgical intervention is reduced to the formation of an aqueous humor outflow tract, which reduces intraocular pressure and eliminates congenital glaucoma. The method and scheme of the operation is chosen in each case strictly individually. Depending on the clinical picture and structural features of the eyeball, goniotomy, sinustrabeculectomy can be performed. drainage operations, laser cyclophotocoagulation or cyclocryocoagulation.
The prognosis of congenital glaucoma with timely diagnosis and surgery is most often favorable, but if the treatment is delayed, visual impairments of various severity are possible. After elimination of glaucoma, at least three months of dispensary observation by an ophthalmologist is necessary.
General characteristics of the disease
Under the medical term "glaucoma" it is customary to understand a whole group of severe ophthalmic pathologies. The disease got its name from the Greek word "????????", the literal translation of which means "blue clouding of the eyes." Such an exotic name of the disease is due to the special color of the pupil. With glaucoma, it becomes a specific blue-green color, acquires an extended immobile state and leads to complete blindness.
Signs of glaucoma can be diagnosed in a person of any age. However, glaucoma occurs most frequently in the elderly. So, for example, cases of congenital glaucoma are diagnosed in only one child for 15-20 thousand children in the first months of life. In persons over 75 years of age, diagnosed cases of glaucoma are already more than 3%.
Causes of glaucoma
At the moment, there is no consensus in medical scientific circles about the causes and mechanisms of glaucoma development. As one of the versions, the theory of the influence of increased intraocular pressure is considered.
It is believed that systematic or intermittent increased IOP can lead to trophic disorders in the structure of the eye, fluid outflow disorders and other complications that cause retinal and optic nerve defects in glaucoma.
The version about the multifactorial nature of the disease with glaucoma is also quite common. The combination of factors that cause glaucoma includes hereditary causes, anomalies in the structure of the organs of vision, trauma, pathology of the nervous, vascular and endocrine systems.
According to this theory, the summing action of all or several of the above factors can trigger the mechanism for the development of glaucoma.
More than 60 different types of disease with specific symptoms are grouped under the term "glaucoma". Glaucoma of any of these types is primarily characterized by damage to the fibers of the optic nerves. Over time, the process passes into the stage of complete atrophy of the visual function.
The earliest symptom of glaucoma is poor outflow of intraocular fluid from the eyeball. It is followed by a deterioration in the blood supply to the tissues of the eye, hypoxia and ischemia of the optic nerves. Lack of oxygen to the tissues of the eye, as one of the signs of glaucoma, leads to the gradual destruction and atrophy of the optic fibers.
Some of them may be in a state of so-called parabiosis (sleep). This allows you to restore the function of the eye with timely treatment of glaucoma.
Types of glaucoma
Congenital glaucoma is most often genetically predetermined or caused by intrauterine infections. Symptoms of this type of glaucoma manifest themselves in the first weeks of life. A child is born with high intraocular pressure, bilateral enlargement of the cornea or the entire eyeball. In everyday life, congenital glaucoma is sometimes called dropsy of the eye or bull's eye.
Juvenile or youthful glaucoma is diagnosed in children older than 3 years. In late cases of manifestation of signs of glaucoma, the disease can manifest up to 35 years. At an older age, diagnosed glaucoma is already referred to as adult and can be primary or secondary.
Secondary glaucoma is commonly understood as clouding of the pupil and signs of optic nerve atrophy, which have become a complication of another ophthalmic disease.
Types and stages of primary glaucoma
Primary glaucoma is the most common type of the disease. It is closed and open angle.
The clinical symptoms of open-angle glaucoma include slow progression of the disease, the absence of any discomfort in the patient, the appearance of the effect of rainbow circles at a late stage of the disease, and gradual blurred vision. Open-angle glaucoma usually affects both eyes at once, but develops asymmetrically (at a different pace in both eyes).
Angle-closure glaucoma is more often diagnosed in women, as predisposing factors for this type of disease are the small size of the eye. Symptoms of this type of glaucoma include the presence of acute bouts of vision loss. Under the influence of nervous shocks, overwork or prolonged work in an uncomfortable position during an attack, a sharp blurred vision occurs, pain in the eyes, nausea, and vomiting can be observed. Then the patient enters a state of preglaucoma with a period of relatively normal vision.
Depending on the severity of the disease, glaucoma is divided into four stages of glaucoma:
Diagnosis of glaucoma
The effectiveness of glaucoma treatment depends on timely diagnosis of the disease. The leading role in it is the determination of intracranial pressure indicators using tonometry or elastotonometry. The quality of intraocular fluid outflow in glaucoma is studied through the use of electronic tonography.
The perimetry method for measuring the boundaries of vision, as well as gonioscopy, are also of high value in the diagnosis of the disease. With the help of the last named method, the structures of the anterior chamber of the eye are examined. To find out qualitative and quantitative disorders in the structure of the optic nerves allows the use of scanning laser ophthalmoscopy.
Each of these methods is highly informative, so only one of them can be used in dynamic monitoring of the effectiveness of glaucoma treatment.
Glaucoma treatment
Treatment for glaucoma can be medical or surgical. Operations for glaucoma, in turn, are also of two types: traditional, performed using a microsurgical scalpel or laser.
The basis for the medical treatment of glaucoma are three directions:
The leading role in the drug treatment of glaucoma has ophthalmohypotensive therapy (lowering IOP). The other two directions are of an auxiliary nature. For example, they use a natural plant complex from Dr. Pankov to treat diseases of the organs of vision.
The use of conservative treatment of glaucoma is indicated only in the early stages of the disease. In case of grade III-IV glaucoma and the ineffectiveness of drug therapy in relieving an acute attack, a surgical operation is recommended.
Laser surgery for glaucoma allows you to eliminate obstacles to the outflow of intraocular fluid. The technique of laser surgery for glaucoma involves the use of iridectomy or trabeculoplasty techniques. Their essence is to create a microexplosion for local tissue rupture or inflicting a burn with subsequent scarring.
The advantages of laser surgery for glaucoma include a short rehabilitation period, outpatient conditions and local anesthesia during the application of the technique. The main disadvantage of laser surgery for glaucoma is the limited effect. At the stage of mature glaucoma, only radical surgery is used.
The disease is treated surgically using several types of techniques:
There is no single standard in the application of one or another type of operation for glaucoma. In each case, the type of operation for glaucoma is selected individually.
Alternative treatment of glaucoma
The prevalence of the disease has led to the emergence of a huge number of methods of folk treatment of glaucoma. Some of them, for example, medical nutrition, the use of sunglasses, breathing exercises, air procedures are welcomed by official medicine.
However, it must also be admitted that official medicine is skeptical about many methods of treating glaucoma with folk remedies: be it infusions of duckweed, wood lice, lotions with aloe juice, instillation of honey into the eyes, etc.
Plan
Introduction
Autosomal recessive inheritance pattern
Autosomal dominant inheritance pattern
floor-linked
For all types of inheritance
Conclusion
Used Books
Introduction
In recent decades, the role of heredity in the etiology of eye diseases has increased significantly. It is known that 4 - 6% of the world's population suffer from hereditary ailments. About 2000 human diseases are hereditary, of which 10-15% are eye diseases, the same number are systemic diseases with eye manifestations. Mortality and hospitalization of these patients are the highest, therefore, early diagnosis and treatment of such diseases is not only a medical problem, but also a national one.
Children are especially vulnerable to hereditary and congenital defects. According to Canadian geneticists, congenital deformities account for 18.4%, most of which are genetically determined. Mortality in these diseases reaches 30%.
There is information about 246 pathological genes that cause congenital anomalies of the organ of vision, which manifest themselves in isolation or in combination with damage to other organs and systems. Of these, dominant are determined by 125 genes, recessive - by 91 genes, sex-related - by 30 genes. The role of hereditary factors in the etiology of the disease of the organ of vision was revealed in 42.3% of cases.
Many anomalies arise in connection with the abnormal development and formation of the eye or its individual components at different periods of ontogeny. They can develop in the very early stages of eye formation under the influence of many physical, chemical, teratogenic agents and dysfunction of hormonal processes. For example, microphthalmos is a consequence of disorders that have arisen in the phase of formation of the eye bubble. Exposure to harmful factors at later stages of eye development leads to the formation of defects in the lens, the retina of the optic nerve. However, it should be noted that the occurrence of these developmental defects may be the result of phenocopy (a hereditary change in the phenotype of an organism caused by environmental factors and copying the manifestation of any known hereditary change - a mutation in this organism).
Progress in the prevention of congenital eye diseases lies in the correct control of factors that can affect the disease of the body of a pregnant woman. Proper prenatal care and appropriate nutrition provide favorable conditions for the development of the fetus. After clarifying the diagnosis and establishing the type of inheritance of the disease, the ophthalmologist, together with a geneticist and other medical specialists, must determine the risk of such a defect in the offspring. Medico-genetic consultations contribute to the prevention of blindness from many hereditary eye diseases.
Hereditary pathology of the organ of vision in an autosomal recessive type of inheritance
Autosomal recessive inheritance occurs only when two heterozygotes are married. Therefore, such signs are found when the parents are closely related. The lower the concentration of an autosomal recessive gene in a population, the greater the likelihood of its implementation with the consanguinity of the parents.
Anophthalmos is the congenital absence or loss of one or both eyeballs. It happens true and imaginary. True anophthalmos is most often unilateral, associated with underdevelopment of the forebrain or with a violation of the “lacing off of the optic nerve. Imaginary anophthalmos is due to a delay in the development of the eyeball. On the x-ray of the skull with true anophthalmos, the optic opening is not detected, with an imaginary one it is always present.
Nystagmus (eye trembling) - fast and infrequent voluntary eye movements caused by central or local causes, due to a peculiar form of clinical spasms of the oculomotor muscles. Movements are made in the horizontal, vertical and rotational direction. Nystagmus develops when visual impairment is congenital or acquired in early childhood, when there is no fixation by the yellow spot of the retina. Nystagmus causes no trouble to patients, but they suffer greatly from a weakness of vision, which is difficult to correct. With age, its intensity may decrease. Nystagmus can also manifest itself in certain diseases of the central nervous system, with damage to the labyrinth, etc. Treatment is most often unsuccessful. The cause itself must be eliminated.
Cryptophthalmos - there is a deformation of the eyelids and the entire anterior part of the eyeball. Cryptophthalmos is often accompanied by pronounced facial deformities, syndactyly (fusion of arms and legs, for example, the little finger with the ring finger), genital anomalies, etc.
Retinoblastoma is a true malignant neoplasm of the retina that occurs in children at an early age (from a few months to 2 years). In 15% of cases, it can be bilateral. The disease is not noticeable at first, but when the disease reaches a significant size and approaches the back surface of the lens, the parents notice, as it were, the glow of the pupil. In this case, the eye is blind, the pupil is wide, a yellowish-white reflex is visible from the depth of the pupil. This whole complex of symptoms is called "amaurotic cat's eye." Retinoblastoma develops from immature glial elements of the retina and is initially visible as a thickening of the retina in a limited area. If the eye is not removed in time, the tumor grows into the orbit and the cranial cavity. Treatment is early removal of the eye followed by radiotherapy. Attempts of X-ray therapy, chemotherapy did not give convincing positive results.
Retinal glioma - a malignant neoplasm of the optic nerve, a tumor of glia (interstitial tissue of the central nervous system), grows slowly, reaching the size of a nut or a goose egg. It can lead to complete blindness and even death. The tumor most often develops at an early age. It is not excluded the defeat of older people. The first signs of tumors of the optic nerve are reduced vision and changes in the visual field. Exophthalmos grows slowly. In this case, the eye usually protrudes forward, its mobility, as a rule, is preserved in full. Treatment is surgical.
Hereditary pathology in autosomal dominant inheritance
Autosomal dominant inheritance of anomalies is characterized primarily by significant phenotypic variability: from a barely noticeable to an excessively intense trait. As it is passed down from generation to generation, this intensity increases more and more. Except for the inheritance of blood properties, modern anthropogenetics so far has information mainly only about rare traits, many of which are inherited according to Mendel's laws or represent a case of additions to them.
Astigmatism - discovered at the end of the 18th century. Astigmatism is a combination of different types of refraction or different degrees of one type of refraction in one eye. In astigmatic eyes, the two perpendicular planes of section with the greatest and least refractive power are called the main meridians. Most often they are located vertically or horizontally. But they can also have an oblique arrangement, forming astigmatism with oblique axes. In most cases, refraction in the vertical meridian is stronger than in the horizontal. Such astigmatism is called direct. Sometimes, on the contrary, the horizontal meridian refracts more than the vertical - reverse astigmatism. Distinguish between right and wrong. Incorrect usually of corneal origin. It is characterized by local changes in the refractive power on different segments of the same meridian and is caused by diseases of the cornea: scars, keratoconus, etc. The correct one has the same refractive power throughout the entire meridian. This is a congenital anomaly, inherited and changes little during life. People suffering from astigmatism (about 40 - 45% of the world's population) need optical correction, that is, they cannot see objects in different planes without glasses. It is eliminated with the help of glasses with cylindrical glasses and with the help of contact lenses.
Hemerolopia is a permanent impairment of twilight vision (night blindness). The central vision decreases, the field of vision gradually concentrically narrows.
Coloboma - a defect in the edge of the eyelid in the form of a triangular or semicircular notch. It is more often observed on the upper eyelid in its middle third. Often combined with other facial deformities. Treatment - with these anomalies, plastic surgery gives good results.
Aniridia - absence of the iris, severe congenital pathology of the vascular tract of the eye. There may be partial or almost complete aniridia. There is no need to talk about complete aniridia, since at least slight remnants of the iris root are found histologically. With aniridia, there are frequent cases of congenital glaucoma with symptoms of eyeball distension (hydrophthalmos), which depend on the fusion of the anterior chamber angle with embryonic tissue. Aniridia is sometimes associated with anterior and posterior polar cataracts, lens subluxation, and rarely with lens coloboma.
Microphthalmos - underdevelopment of the entire eyeball, with a decrease in all its sizes, a "small eye".
Ectopic lens - displacement of the lens of the lens. The most typical example is the ectopia of the lens, which is observed with a family-hereditary lesion of the entire musculoskeletal system, which is expressed in lengthening of the distal phalanges of the fingers and toes, lengthening of the limbs, weakness of the joints. Severe endocrine disorders. This disease is called arachnodactyly, or Marfan's syndrome. In the eyes, a symmetrical displacement of the lens is found. More often the lens is displaced upward and inward or upward and outward.
The displacement of the lens may be accompanied by the development of cataracts.
The proportion of congenital and hereditary eye diseases is large. They currently account for 71.75% of all causes of blindness and low vision in children.
The following types of congenital and hereditary eye pathology are considered below.
- Local or systemic disorders of embryonic development due to:
a) damage to the genetic apparatus of cells during viral and toxoplasmic effects;
b) violations of embryogenesis due to various infections and intoxications suffered by the mother during pregnancy. - Congenital hereditary lesions caused by chromosomal or gene pathology, as well as genetically determined metabolic disorders.
- Congenital and congenital-hereditary clinically defined syndromes, most often associated with chromosomal diseases or gene mutations.
The regularity of the combination of some signs of eye pathology in the syndromes has been established. For example, microphthalmos is often combined with colobomas of the iris and choroid, cataracts - with aniridia, ectopia of the lens, high congenital myopia - with remnants of embryonic tissues, colobomas of the choroid, retinitis pigmentosa - with keratoconus. A number of congenital defects on the part of the eyes and the whole body are associated with certain chromosomal aberrations and changes in the karyotype.
The main methods for diagnosing these diseases are clinical and genetic methods - genealogical, cytogenetic, cytological, biochemical, etc.
This section provides information and photos on the following diseases:
- congenital and congenital hereditary diseases of the anterior part of the eye and its appendages (eyelids, cornea, iris, lens);
- congenital and congenital-hereditary lesions of the fundus (the most frequently inherited signs in families with congenital myopia, retinal dystrophy, optic nerve atrophy, etc.).
277. Congenital dermoid tumor of the upper eyelid (a, b).
278. Congenital complete left-sided ptosis.
279. Congenital partial left-sided ptosis.
280. Congenital complete bilateral ptosis and epicanthus.
281. Congenital partial bilateral ptosis and epicanthus.
282. Marcus-Gunn syndrome.
a - left-sided palpebro-mandibular synkinesis;
b - decrease in ptosis when opening the mouth and retracting the lower jaw.
283. Congenital extensive angioma of the face and head (recessive type of inheritance).
284. Angioma of the lower eyelid.
285. Angioma of the upper and lower eyelids.
286. Neurofibroma of the eyelids, conjunctiva of the eyeball and orbit.
287. Advanced neurofibroma of the eyelid and orbit.
288. Neurofibroma of the eyelids and conjunctiva of the eyeball 10 years after surgery.
289. Congenital bilateral dermoid of the conjunctiva and cornea,
a - right eye;
b - left eye.
290. Fleischer's pigment ring - unilateral deposition of homosiderin in the form of a brown half-ring along the periphery of the cornea on the border with the limbus.
291. Congenital, hereditary glaucoma (type of inheritance autosomal dominant).
a - in the father: clouding of the cornea, congestive perilimbal injection of blood vessels (symptom of "jellyfish"). The anterior chamber is small, the pupil is wide;
b - d - in the son: the cornea of both eyes is enlarged, edematous, the anterior chamber is deep. Dystrophy of the iris.
292. Bilateral megalocornea (a, b) with hydrophthalmos (corneal diameter 16-17 mm), hypertelorism, myopia, iris hypoplasia in homozygous twins. The limb is expanded, the anterior chamber is deep. One of the twins (b) has a divergent strabismus in the right eye.
293. Congenital supra-pupillary membrane (a, b).
294. Congenital ectopic pupil with coloboma of the iris, partial clouding of the lens.
295. Congenital ectopic pupil with iris coloboma.
296. Congenital, hereditary subluxation of the lens in both eyes in two brothers P.
a, b - Alexander;
c, d - Oleg.
297. Congenital cataract with saturated opacities in the equatorial region in the form of hairpins, planted on the edge of the cloudy disk ("riders").
298. Congenital zonular nuclear cataract (stereophoto).
299. Congenital zonular cataract with clouding of the posterior capsule in the form of a triangle (stereophoto).
300. Congenital zonular cataract with clouding at the pole of the anterior capsule.
301. Abortive form of congenital zonular cataract - cataracta pulvurulenta zonularis, consisting of densely located dots surrounding the nucleus.
302. Congenital and hereditary layered cataracts traced in 4 generations of the Ya family (recessive type of inheritance).
Brother. Congenital layered cataract with compacted nucleus:
a - right eye;
b - left eye. Sister. Congenital layered "cataract with a diameter of opacification of 5 mm;
c - right eye; d - left eye.
303. Remains of myelin fibers of the optic nerve in high congenital myopia in the family of P.
Father:
a - right eye;
b-left eye. Son:
c - right eye; above and below at the optic disc;
d - left eye.
304. Anomalies in the development of the fundus in congenital hereditary myopia (dominant type of inheritance). Connective tissue covers the entire optic nerve head and extends into the macular region - membrane prepapilaris.
305. Anomalies in the development of the fundus in congenital hereditary myopia (dominant type of inheritance). Coloboma of the entrance of the optic nerve head, true staphyloma and underdevelopment of the choroid in the prenatal period.
306. Anomaly in the development of the fundus in congenital hereditary myopia (dominant type of inheritance). The entire optic nerve is covered with connective tissue, only in the center of it there is a gap through which a section of a normal disc is visible. The connective tissue also covers the vessels of the membrane prepapilaris.
307. Anomalies in the development of the fundus in congenital, hereditary myopia (recessive type of inheritance). Macular coloboma. The vessels exit the coloboma from the side of the choroid and anastomose with the vessels of the retina.
308. Anomalies in the development of the fundus in congenital hereditary myopia (recessive type of inheritance). Congenital absence of the temporal half of the disc.
309. Hypergliosis near the optic disc. Remains of the artery of the primary vitreous body - a. hyaloidea.
310. Remains a. hyaloidea.
311. Changes in the fundus of the eye in congenital myopia with toxoplasmosis. Extensive chorioretinal focus in the macular region with pigment deposition.
312. Changes in the fundus of the eye in congenital myopia with toxoplasmosis. Extensive chorioretinal focus in the macular region with pigment deposition.
313. Changes in the fundus of the eye in congenital myopia in the E. family (dominant type of inheritance). Mother:
a - right eye. Extensive myopic staphyloma, choroid atrophy, pigmentation in the macular region;
b - left eye. The optic disc is oval, with a large myopic cone. Father:
c - left eye. Extensive myopic cone, macular pigmentation. Son:
d - right eye. Extensive myopic cone at the disc, underdevelopment of the choroid, underdevelopment of the macular area. Daughter:
d - right eye. Oval disc, extensive myopic cone.
314. Congenital myopia and ptosis in the G. family (dominant type of inheritance).
Father:
a - congenital ptosis, high myopia. Eldest daughter:
b-congenital ptosis, high myopia. Youngest daughter:
c - congenital ptosis, high myopia. Father:
d - fundus of the left eye, myopic cone. Eldest daughter:
e - fundus: right eye - myopic cone; mild degree of atrophy of the choroid at the optic nerve head. Youngest daughter:
f - the fundus of the right eye, an extensive coloboma of the choroid at the optic nerve head.
315. Changes in the fundus of the eye in congenital myopia in two twins and their mother in the T. family (dominant type of inheritance).
a - Yuri T.;
b - Igor T. Yuri T.:
c - right eye: myopic cone, vascular atrophy in the parapapillary region, albinism of the fundus;
d - left eye: myopic cone with pigment deposition. From Igor T.:
e - right eye: myopic cone, atrophy of the choroid in the parapapillary region, albinism of the fundus;
e - left eye: myopic cone, albinism of the fundus;
g-left eye: remains of the primary vitreous body. The mother of twins:
h - right eye: extensive myopic cone, albinism of the fundus.
316. Congenital and hereditary underdevelopment of the choroid at the optic disc, macular area, amblyopia, high hypermetropia in the family of Ch.
a - Evgeny Ch.;
b - Vladimir Ch. Evgeny Ch.:
c - right eye. Underdevelopment and atrophy of the choroid near the optic disc, an enlarged scleral ring. Vladimir C.:
d - left eye. Underdevelopment and atrophy of the choroid in the parapapillary region, expressed along the vessels, in the mother of twins
d - right eye. Underdevelopment of the choroid in the macular region, pigmented foci;
f - left eye: atrophy of the choroid in the paramacular region, pigmentary foci.
317. Congenital hereditary atrophy and aplasia of the optic discs (autosomal recessive inheritance).
At my brother's:
a - right eye. Congenital aplasia and atrophy of the optic disc. Disc tissue is preserved only in the nasal part between the vascular bundle and the edge of the disc. In the temporal part, a cribriform plate is exposed by 3/4. Around the optic nerve - underdevelopment of the choroid ring-shaped. At the sister:
b - right eye: congenital atrophy and aplasia of the optic disc with a more pronounced atrophic area in the temporal half.