Purpose: The purpose of this study was to determine whether the genetic polymorphisms of complement factor 3 (C3) are associated with neovascular age-related macular degeneration (AMD) in the Chinese population.
Methods: A total of 123 unrelated Chinese Han patients with neovascular AMD and 130 control subjects were recruited. Their six single-nucleotide polymorphisms (SNPs) in the C3 gene, one in the complement factor H (CFH) gene and two in the complement factor B (CFB) gene were characterized. Their genotypes, allele frequencies, and odds ratios were analyzed.
Results: The G allele of the C3 IVS2 rs2250656, but not other tested C3 SNPs of rs2230205, rs10411506, rs2230199, rs339392, and rs163913, was significantly associated with a reduced risk for AMD in the Chinese population (OR 0.605, 95% CI 0.39-0.93, p = 0.023), even after adjusting for age, gender, smoking status, CFH rs1061170, CFB rs4151667, and CFB rs641153 allele status (OR 0.58, 95% CI 0.35-0.96, p = 0.033). However, the C3 haplotype of A-A-C-A-T-T was identified as a statistically significant risk factor for neovascular AMD (OR 1.41, 95% CI 1.02-1.94). Furthermore, the C allele of the CFH rs1061170, but not the CFB rs4151667 and rs641153, was significnatly associated with increased risk for AMD (OR 3.09, 95% CI 1.55-6.15, p < 0.001).
Conclusion: The G allele of C3 IVS2 rs2250656 may be a significantly protective factor for neovascular AMD in the Chinese population. This, together with low MAF of C3 R102G, may be partially responsible for the low prevalence of AMD in the Chinese population.