Associations Between the T280M and V249I SNPs in CX3CR1 and the Risk of Age-Related Macular Degeneration

PURPOSE. Two common single nucleotide polymorphisms (SNPs) in the CX3CR1 gene, T280M and V249I, have been reported to affect the risk of age-related macular degeneration (AMD) in several studies. The aim of the present study was to combine all published data on the relationship between these two variants and AMD susceptibility in a meta-analysis to clarify this association. METHODS. MEDLINE, EMBASE, and ISI Web of Science were searched for all eligible studies on the relationship between AMD and T280M and V249I variants. The pooled odds ratio (OR) with 95% confidence intervals (CIs) for each SNP in the allele frequency, homozygote, second codominant genotype, and dominant genotype models were calculated to evaluate the strength of this association. RESULTS. A total of 3017 AMD cases and 4096 controls from eight studies were involved in this meta-analysis. Both T280M and V249I SNPs exhibited significant associations with increased risk of AMD in the allele (T versus C: OR = 1.43, 95% CI: 1.06-1.91; A versus G: OR = 1.25, 95% CI: 1.01-1.55) and homozygous models (TT versus CC: OR = 2.11, 95% CI: 1.00-4.43; AA versus GG: OR = 1.27, 95% CI: 1.00-1.61), while no significance association was observed for the codominant genotype model. Moreover, studies showing high linkage disequilibrium between these two variants demonstrated a significantly stronger connection between these SNPs and AMD risk, compared with the moderate linkage disequilibrium group. CONCLUSIONS. Significant evidence for a relationship between T280M and V249I variants in CX3CR1 in the homozygote state with increased susceptibility to AMD was reported. Further studies are needed to confirm these findings.