Discovery and characterization of glaucoma associated genetic variations

Abstract

Genetic factors contribute to virtually every human disease, conferring susceptibility or re-sistance, or influencing interaction with environmental factors. Single nucleotide polymorphisms (SNP) are has been suggested as a powerful tool to identify genes for complex disease. In this study, novel genes and genetic variations associated with or responsible for glaucoma development and pro-gression were discovered using case-control association study and molecular and cellular mechanisms underlying glaucoma etiology was elucidated. To identify genes and genetic variants associated with glaucoma, specifically primary open-angle glaucoma (POAG) susceptibility, a case-control study was performed for 208 glaucoma cases (188 POAGs) and 933 controls. Thirty-two candidate genes showing drastically different expression patterns between glaucomatous and normal tissues were chosen and 134 tag SNPs covering those 32 candidate genes were genotyped. Two SNPs from NREP showed significant association with glauco-ma and also POAG susceptibility (P < 0.05). For fine-mapping of the candidate gene, additional 12 tag SNPs were selected and genotyped. Five SNPs located on NREP promoter were significantly associated with glaucoma and as well as POAG (0.00051 ≤ P ≤ 0.022 in co-dominant model). The haplotype CGCGG, one of haplotypes reconstructed with associated 5 SNPs, consisting of a risk allele of each SNP had 1.38-fold higher risk of POAG than the haplotype AAGCC with a non-risk allele (P = 0.0060). Also, the risk haplotype CGCGG showed significantly reduced promoter activity (P < 0.05). Since NREP is a down-regulated in trabecular meshwork tissues under induced-high IOP and risk haplotype of NREP also showed low expression activity, we decided to examine the biological consequences of NREP knockdown. We first assessed apoptosis rate which is related with retinal gan-glion cell death, one of the POAG phenotype in NREP-knockdown cell. To explore the cell death sensitivity of NREP-...