NEW GENETIC MARKERS ASSOCIATED WITH SUSCEPTIBILITY TO EXFOLIATION SYNDROME AMONG GEORGIAN POPULATION

The aim of this study was to identify susceptibility variants of CACNA1A, POMP, TMEM136, AGPAT1, RBMS3, and SEMA6A genes for Exfoliation Syndrome (XFS) and Exfoliation Glaucoma (XFG) by a case-control association study approach among Georgian population. Self-reported Georgian subjects were recruited between 2015 and 2017 at a specialized ophthalmic center. Patients underwent detailed ophthalmic examination to diagnose or exclude Exfoliation Syndrome and Exfoliation Glaucoma. Patients underwent peripheral blood sampling. Genome-Wide Association Study (GWAS) was performed using Illumina OmniExpress Microarray (USA). One hundred and thirty-two XFS patients (including XFG-affected individuals) and 199 healthy subjects were included into the study. Six genes CACNA1A rs4926244, POMP rs7329408, TMEM136 rs11827818, AGPAT1 rs3130283, RBMS3 rs12490863 and SEMA6A rs10072088 variants were identified. The A alleles of SEMA6A and POMP genes are likely the risk factors of disease development in Georgians with p=0.001; OR= 1.8, 95% CI 1.2676 to 2.6973 and p=0.001; OR=1.6, 95% CI 0.9931 to 2.5634, respectively. SEMA6A homozygotes have 4 times greater risk compared to normal individuals, with p<0.004; OR=4.0, 95% CI 1.1531 to 13.9903. The G allele of CACNA1A in homozygous state increases the risk up to 3-fold with p<0.05, OR=3.15, 95% CI 0.9275 to 10.6658. The A alleles of SEMA6A and POMP increased XFG susceptibility more than 3 times (p=0.04; OR= 3.4; 95% CI: 1.2676 to 2.6973 and p=0.02; OR= 2.7; 95% CI: 0.9931 to 2.5634, respectively). Three high-risk genes have been identified in connection to XFS in Georgian population. Two genes are relevant to XFG. Three other previously described genes are not associated with the disease development.