Frequent Genetic Variants of Autosomal Recessive Nonsyndromic Forms of Inherited Retinal Diseases in the Russian Federation

Abstract

Inherited retinal diseases (IRDs) are a clinically heterogeneous group of retinal pathologies associated with vision loss due to dysfunction or degeneration of photoreceptor and retinal pigment epithelium. Autosomal recessive forms of IRDs account for more than 55% of all diseases in this group on average worldwide. This study presents data on frequent pathogenic and likely pathogenic variants in recessive genes of IRDs obtained from a retrospective analysis of high-throughput sequencing data from a large Russian cohort of patients with suspected inherited nonsyndromic retinal pathology. Data from 1470 unrelated patients were analyzed. Pathogenic and likely pathogenic variants were identified in the zygosity required for the development of the disease in 643 patients (43.74%). It was found that nine genes (ABCA4, CNGB3, USH2A, RPE65, CRB1, CNGA3, CEP290, GUCY2D, PDE6H) account for 73.3% of all molecularly confirmed cases of IRDs in Russian patients. An analysis of the spectrum of nucleotide variants of these genes was carried out, and 17 variants were identified that occur with an allelic frequency of more than 1% for each gene. In light of the data obtained, diagnostic systems based on the multiplex ligation-dependent probe amplification reaction (MLPA) were developed. The informativity of the two systems for diagnosing autosomal recessive nonsyndromic forms of inherited retinal diseases is 16.4%, the informativity for all forms of nonsyndromic retinal diseases exceeds 7%. For a group of patients with achromatopsia, a study using one of the systems will make it possible to establish a diagnosis in 62.5% of cases.