title: Systematic review and meta-analysis of the association between complement component 3 and age-related macular degeneration: a HuGE review and meta-analysis.
abstract: The authors performed a meta-analysis to estimate the magnitude of polymorphism effects for the complement component C3 gene (C3) and their possible mode of action on age-related macular degeneration (AMD). The meta-analysis included 16 and 7 studies for rs2230199 and rs1047286, respectively. Data extraction and risk of bias assessments were performed in duplicate, and heterogeneity and publication bias were explored. There was moderate evidence for association between both polymorphisms and AMD in Caucasians. For rs2230199, patients with CG and GG genotypes were 1.44 (95% confidence interval (CI): 1.33, 1.56) and 1.88 (95% CI: 1.59, 2.23) times more likely to have AMD than patients with the CC genotype. For rs1047286, GA and AA genotypes had 1.27 (95% CI: 1.15, 1.41) and 1.70 (95% CI: 1.27, 2.11) times higher risk of AMD than did GG genotypes. These gene effects suggested an additive model. The population attributable risks for the GG/GC and AA/GA genotypes are approximately 5%-10%. Subgroup analysis by ethnicity indicates that these variants are very infrequent in Asians and that the observed gene effects are based largely on the high frequency within Caucasian populations. This meta-analysis supports the association between C3 and AMD and provides a robust estimate of the genetic risk.
authors.affiliation: Section for Clinical Epidemiology and Biostatistics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. raatk@mahidol.ac.th
authors.forename: Ammarin
authors.initials: A
authors.lastname: Thakkinstian
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: McKay
authors.forename: Mark
authors.initials: M
authors.lastname: McEvoy
authors.forename: Usha
authors.initials: U
authors.lastname: Chakravarthy
authors.forename: Subhabrata
authors.initials: S
authors.lastname: Chakrabarti
authors.forename: Giuliana
authors.initials: G
authors.lastname: Silvestri
authors.forename: Inderjeet
authors.initials: I
authors.lastname: Kaur
authors.forename: Xiaoxin
authors.initials: X
authors.lastname: Li
authors.forename: John
authors.initials: J
authors.lastname: Attia
mesh_terms: D000367:Age Factors; D044466:Asian People / Q000235:genetics; D003176:Complement C3 / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D008268:Macular Degeneration / Q000208:ethnology / Q000235:genetics*; D044465:White People / Q000235:genetics
chemical_list: D003176:Complement C3