Joint effects of polymorphisms in the HTRA1, LOC387715/ARMS2, and CFH genes on AMD in a Caucasian population

PURPOSE: To estimate the joint effects of single nucleotide polymorphysms (SNPs) in the genes complement factor H (CFH), HtrA serine peptidase 1 (HTRA1), and age-related maculopathy susceptibility 2 (LOC387715/ARMS2) in a Caucasian age related macular degeneration (AMD) case-control cohort. METHODS: We genotyped three SNPs, rs1061170 (exon 9, CFH), rs11200638 (HTRA1 promoter, −512 bp), and rs10490924 (6.6 kb upstream of HTRA1 in LOC387715/ARMS2) in 333 cases with advanced AMD (choroidal neovascularization [CNV] and geographic atrophy) and 171 age-matched examined controls. Association tests were performed for individual SNPs and jointly with the CFH SNP Y402H. Analyses for interaction were also performed. RESULTS: The linkage disequilibrium measure for two SNPs on 10q26, rs10490924 and rs11200638, is D'=0.8 and all four possible haplotypes of the two SNPs were detected in the samples. The allelic association test for rs11200638 on the promoter of HTRA1 yielded p-values less than 10(−10) for geographic atrophy, less than 10(−16) for neovascularization, and less than 10(−19) for the pooled phenotypes (with an odds ration [OR] of 3.973; 95% confidence interval [CI] 2.928, 5.390). Disease risk is conferred in a dosage-dependent fashion. Similar figures were observed for the LOC387715/ARMS2 SNP. No interaction was detected between either between the 10q26 SNPs or the CFH SNP. CONCLUSIONS: This is the first analysis to show that the two 10q26 SNPs are not in complete linkage disequilibrium. Our studies however show that both the HTRA1 and LOC387715/ARMS2 SNP appear to contribute equally to disease risk (both geographic atrophy and choroidal neovascularization) with no evidence of interaction with CFH.