Evaluation of the association of C5 with neovascular age-related macular degeneration and polypoidal choroidal vasculopathy

Background:Neovascular age-related macular degeneration(AMD)and polypoidal choroidal vasculopathy(PCV)are sight-threatening maculopathies with both environmental and genetic risk factors.We have previously shown relative risks posed by genes of the complement pathways to neovascular AMD and PCV.Methods:In this study,we investigated the haplotype-tagging single nucleotide polymorphisms(SNPs)in the complement component 5(C5)gene in 708 unrelated Chinese individuals:200 neovascular AMD patients,233 PCV patients and 275 controls.Six tagging SNPs in C5 were genotyped.Univariate single SNP association analysis,haplotype-based association analysis and gene-gene interaction analysis between C5 and other AMD-associated genes were performed.Results:The results revealed none of the six tagging SNPs of the C5 gene had a significant association with neovascular AMD or PCV(P>0.05).We also found insignificant haplotype-based association,and no significant SNPSNP interaction between C5 and other genes(including C2-CFB-RDBP-SKIV2L,SERPING1,CETP,ABCG1,PGF,ANGPT2,CFH and HTRA1)for neovascular AMD and PCV.Conclusions:This study showed no statistical significance in the genetic association of C5 with neovascular AMD or PCV in a Hong Kong Chinese population.Further studies in large samples from different populations are warranted to elucidate the role of C5 in the genetic susceptibility of AMD and PCV.