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MODERN IDEAS OF THE BASIS OF GENETIC PREDISPOSITION IN THE
DEVELOPMENT AND COURSE OF MYOPIA
Otabek Azizbekovich Ikramov
https://orcid.org/0000-0001-8220-3378
Associate Professor of the Department of Ophthalmology of the Andijan State Medical
Institute, PhD
Azizbek Fazilovich Ikramov
https://orcid.org/0000-0001-8540-7931
Head of the Department of Ophthalmology of the Andijan State Medical Institute, Doctor of
Medical Sciences, Professor
Keywords.
Myopia, schoolchildren, genetic factors, health status, visual acuity.
Relevance of the problem.
Over the past three decades, there has been an increase in axial
farsightedness among young populations around the world, mainly in West and East-West
Asia. This is caused primarily by hereditary factors, pregnancy defects, and with them the
level of illumination and the color of various colors, the quality of daily diet, outdoor
activities, environmental conditions and a number of other factors. which is explained by
stress factors in preschool organizations and secondary schools. The state of health of
students studying in schools and the degree of their mastery of subjects, resistance to
environmental factors, the functional state of organs and systems, associated mainly with
visual activity and its acuity, are presented in a number of scientific publications.
The genetic determinism of myopia was noted in the three-factor theory of Avetisov E.S.
(1995), according to which refractive errors are formed with the participation of
environmental factors, conditions of visual activity and hereditary factors.
Various studies have shown that myopia can be inherited in both autosomal dominant and
autosomal recessive types. In the first case, the manifestation of the disease occurs mainly in
adolescence with a milder clinical course. In the autosomal recessive inheritance type,
myopia often develops at an early age and tends to progress with the development of
complications.
According to existing ideas, the development of myopia involves increased extensibility of
the sclera, resulting from mutations in one or more genes of the extracellular matrix of the
sclera [Sun Y, Sha Y, 2024]. Also, the development of myopia is associated with a change
in the elastic strength characteristics of the sclera and an increase in the anterior-posterior
axis of the eyeball, a decrease in the content of glycosaminoglycans in the scleral membrane,
a change in the structure of collagen, fibrillin, weakening of cross-links in collagen fibers,
etc. [Iomdina E.N., Tarutta E.P., 2014; Troilo D, Smith EL, 2019; Sun Y, Sha Y, 2024].
Numerous scientific works of ophthalmologists have proven that myopia develops in the
case of a number of genetic diseases accompanied by connective tissue dysplasia, such as
Marfan syndrome, Ehlers-Danlos syndrome, Cohen syndrome, Knobloch syndrome, etc. For
example,changes in the
ACTC1
gene involved in the formation of contractile cells – scleral
myofibroblasts, the
GJD2
gene associated with the regulation of eyeball growth,
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the
GRIA4
gene associated with the metabolism of retinoic acid, the decrease
in
MMP2
expression observed in myopia significantly suppresses the decrease in the
accumulation of the Iα1 collagen chain in the sclera [Markosyan G.A., Tarutta E.P.,
2016; Zhao F, Zhou Q, 2018; At , present, the search for the decisive genetic factors that
determine the hereditary predisposition to myopia continues to be an urgent scientific task.
It is known that the formation of biologically active molecules is controlled by genetic
mechanisms that underlie the regulation of the expression of the genes that code for
them. Gene expression is carried out in the process of implementing the information
encoded in the DNA structure with the formation of an mRNA molecule, then an amino acid
sequence of a protein molecule that performs its intended function.
The level of expression of various genes has a high individual variability. A pathological or
conditionally pathological process, for example, damage to tissue integrity, can lead to
modulation of gene activity. But the level of expression of certain genes is also determined
by the presence of genetic variants – single nucleotide polymorphisms (SNPs), when an
individual has structurally and functionally alternative alleles of a certain gene.
A single nucleotide polymorphism occurs as a result of a point mutation, in which the DNA
sequence of one of two identical regions of homologous chromosomes changes by one
nucleotide. The leading approach to identifying genetic variants associated with
polymorphisms is the study of candidate gene associations in case-control studies.
To assess the contribution of genetic predisposition to the development and course of
myopia, it is necessary to study polymorphic variants of the transforming growth factor beta
1
(
TGFB1
)
gene:
TGFB1
(C509T)
–
rs1800469,
TGFB1
(T869C)
–
rs1800470,
TGFB1
(G915C)
–
rs1800471,
TGFB1
(G800A) – rs1800468, as well as a
polymorphism of the angiotensin-converting enzyme
ACE –
rs4646994 (I/D).
REFERENCES
1. Aprelev A.E. et al. Prevalence of myopia and epidemiological factors that determine its
development // Russian Ophthalmological Journal. – 2022. – Vol. 15. – No. 4. – P. 144-149.
2. Arkhipov G. S., Zyablitskaya A. N., Ivanitskaya Y. N. Influence of Artificial Illumination
Indicators on Myopia Morbidity among Schoolchildren of the Altai Republic // Organizing
Committee of the Conference. – 2016. – P. 211.
3. Kuryazova Z. Kh., Yangieva N. R. Issues of pathogenesis and prevention of myopia
(literature review) // Journal "Medicine and Innovations". – 2021. – No. 3. – P. 54-61.
4. Iomdina E.N., Tarutta E.P. Modern Directions of Fundamental Studies of the
Pathogenesis of Progressive Myopia // Bulletin of the Russian Academy of Medical
Sciences. – 2014. – No3-4, Vol. 69. – P. 44-49.
5. Markosyan, G.A., Tarutta, E.P., Iomdina, E.N., et al. Clinical, functional and
biomechanical aspects of pathogenesis, diagnosis and treatment of congenital myopia:
literature review and analysis of own data. // Russian Pediatric Ophthalmology, 2016. -11
(3), 149-157.
