Analysis of rare variants in the C3 gene in patients with age-related macular degeneration

PLoS One. 2014 Apr 15;9(4):e94165. doi: 10.1371/journal.pone.0094165. eCollection 2014.

Abstract

Age-related macular degeneration (AMD) is a progressive retinal disorder affecting over 33 million people worldwide. Genome-wide association studies (GWASs) for AMD identified common variants at 19 loci accounting for 15-65% of the heritability and it has been hypothesized that the missing heritability may be attributed to rare variants with large effect sizes. Common variants in the complement component 3 (C3) gene have been associated with AMD and recently a rare C3 variant (Lys155Gln) was identified which exerts a large effect on AMD susceptibility independent of the common variants. To explore whether additional rare variants in the C3 gene are associated with AMD, we sequenced all coding exons in 84 unrelated AMD cases. Subsequently, we genotyped all identified variants in 1474 AMD cases and 2258 controls. Additionally, because of the known genetic overlap between AMD and atypical hemolytic uremic syndrome (aHUS), we genotyped two recurrent aHUS-associated C3 mutations in the entire cohort. Overall, we identified three rare variants (Lys65Gln (P=0.04), Arg735Trp (OR=17.4, 95% CI=2.2-136; P=0.0003), and Ser1619Arg (OR=5.2, 95% CI=1.0-25; P=0.05) at the C3 locus that are associated with AMD in our EUGENDA cohort. However, the Arg735Trp and Ser1619Arg variants were not found to be associated with AMD in the Rotterdam Study. The Lys65Gln variant was only identified in patients from Nijmegen, the Netherlands, and thus may represent a region-specific AMD risk variant.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alleles
  • Amino Acid Substitution
  • Case-Control Studies
  • Complement C3 / genetics*
  • Female
  • Genetic Predisposition to Disease
  • Genetic Variation*
  • Genome-Wide Association Study
  • Genotype
  • Humans
  • Macular Degeneration / diagnosis
  • Macular Degeneration / genetics*
  • Male
  • Middle Aged
  • Polymorphism, Single Nucleotide
  • Sequence Analysis, DNA
  • Severity of Illness Index

Substances

  • Complement C3

Grants and funding

This study was supported by the Netherlands Organization for Scientific Research (Vidi Innovational Research Award 016.096.309 to AIDH) and the Foundation Fighting Blindness USA (grant C-GE-0811-0548-RAD04 to AIDH). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.