Effect of the Gas6 c.834+7G>A polymorphism and the interaction of known risk factors on AMD pathogenesis in Hungarian patients

PLoS One. 2012;7(11):e50181. doi: 10.1371/journal.pone.0050181. Epub 2012 Nov 29.

Abstract

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly in the developed world. Numerous genetic factors contribute to the development of the multifactorial disease. We performed a case-control study to assess the risk conferred by known and candidate genetic polymorphisms on the development of AMD. We searched for genetic interactions and for differences in dry and wet AMD etiology. We enrolled 213 patients with exudative, 67 patients with dry AMD and 106 age and ethnically matched controls. Altogether 12 polymorphisms in Apolipoprotein E, complement factor H, complement factor I, complement component 3, blood coagulation factor XIII, HTRA1, LOC387715, Gas6 and MerTK genes were tested. No association was found between either the exudative or the dry form and the polymorphisms in the Apolipoprotein E, complement factor I, FXIII and MerTK genes. Gas6 c.834+7G>A polymorphism was found to be significantly protective irrespective of other genotypes, reducing the odds of wet type AMD by a half (OR = 0.50, 95%CI: 0.26-0.97, p = 0.04). Multiple regression models revealed an interesting genetic interaction in the dry AMD subgroup. In the absence of C3 risk allele, mutant genotypes of both CFH and HTRA1 behaved as strongly significant risk factors (OR = 7.96, 95%CI: 2.39 = 26.50, p = 0.0007, and OR = 36.02, 95%CI: 3.30-393.02, p = 0.0033, respectively), but reduced to neutrality otherwise. The risk allele of C3 was observed to carry a significant risk in the simultaneous absence of homozygous CFH and HTRA1 polymorphisms only, in which case it was associated with a near-five-fold relative increase in the odds of dry type AMD (OR = 4.93, 95%CI: 1.98-12.25, p = 0.0006). Our results suggest a protective role of Gas6 c.834+7G>A polymorphism in exudative AMD development. In addition, novel genetic interactions were revealed between CFH, HTRA1 and C3 polymorphisms that might contribute to the pathogenesis of dry AMD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Alleles
  • Apolipoproteins E / genetics
  • Case-Control Studies
  • Female
  • Genetic Predisposition to Disease*
  • Genotype
  • Humans
  • Hungary
  • Intercellular Signaling Peptides and Proteins / genetics*
  • Macular Degeneration / genetics*
  • Male
  • Middle Aged
  • Models, Genetic
  • Molecular Biology
  • Odds Ratio
  • Polymorphism, Genetic*
  • Regression Analysis
  • Risk
  • Risk Factors

Substances

  • Apolipoproteins E
  • Intercellular Signaling Peptides and Proteins
  • growth arrest-specific protein 6

Grants and funding

This study was supported by by the Hungarian Research Fund OTKA K68616 (to A.B.) and by the Social Renewal Operational Programme TAMOP 4.2.1./B-091/1/KONV-2010-0007 project (to A.B. and I.B.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.