Genetic aspects of keratoconus development

Keratoconus (KC) is the most common form of keratoectasia characterized by changes in corneal topography and its thinning, stretching, and protrusion. The hereditary or genetic theory of keratoconus development is widely recognized. To date, a large number of candidate genes have been investigated in patients with KC. One of the most important of them are the gene encoding a homeodomain-containing protein that belongs to the subfamily of paired-like homeodomain proteins (VSX1), superoxidedismutase 1 (SOD1) gene, and the gene of lysyloxidase (LOX). The linkage analysis reveals over 17 chromosomal regions mutations in which can lead to the development of KC. In families with a hereditary form of keratoconus by GWAS analysis, the association of central corneal thickness (CCT) with a number of genetic loci is revealed. Thus, diverse results of genetic studies and a large number of identified chromosomal regions associated with keratoconus, firstly, show marked genetic heterogeneity of the disease and, secondly, are associated with challenges in DNA diagnosis of this disease. However, there are prerequisites that keratoconus belongs to both hereditary and genetically caused diseases and identified genetic variants are specific both to individual populations and to certain ethnic groups in general.