Gene-gene interaction in folate-related genes and risk of neural tube defects in a UK population

J Med Genet. 2004 Apr;41(4):256-60. doi: 10.1136/jmg.2003.010694.

Abstract

Objective: To investigate the contribution of polymorphic variation in genes involved in the folate-dependent homocysteine pathway in the aetiology of neural tube defects (NTD).

Design: Case-control association study.

Subjects: A total of 530 individuals from families affected by NTD, 645 maternal controls, and 602 healthy newborn controls from the northern UK.

Main outcome measures: Seven polymorphisms in six genes coding for proteins in the folate-dependent homocysteine pathway (MTHFR 677C-->T, MTHFR 1298A-->C, MTRR 66A-->G, SHMT 1420C-->T, CbetaS 844ins68, GCPII 1561C-->T, RFC-1 80G-->A). The impact of each polymorphism and the effect of gene-gene interactions (epistasis) upon risk of NTD were assessed using logistic regression analysis.

Results: The MTHFR 677C-->T polymorphism was shown to represent a risk factor in NTD cases (CC v CT+TT odds ratio (OR) 2.03 [95% confidence interval (CI) 1.09, 3.79] p = 0.025) and the MTRR 66A-->G polymorphism was shown to exert a protective effect in NTD cases (AA v AG+GG OR 0.31 [95% CI 0.10, 0.94] p = 0.04). When statistical tests for interaction were conducted, three genotype combinations in cases (MTRR/GCPII; MTHFR 677/CbetaS; MTHFR 677/MTRR) and one combination in case mothers (CbetaS/RFC-1) were shown to elevate NTD risk. Maternal-fetal interaction was also detected when offspring carried the MTHFR 677C-->T variant and mothers carried the MTRR 66A-->G variant, resulting in a significantly elevated risk of NTD.

Conclusion: Both independent genetic effects and gene-gene interaction were observed in relation to NTD risk. Multi-locus rather than single locus analysis might be preferable to gain an accurate assessment of genetic susceptibility to NTD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Case-Control Studies
  • Epistasis, Genetic*
  • Female
  • Folic Acid / metabolism*
  • Gene Frequency
  • Genetic Predisposition to Disease*
  • Genotype
  • Homocysteine / metabolism
  • Humans
  • Male
  • Neural Tube Defects / genetics*
  • Polymorphism, Genetic*
  • United Kingdom

Substances

  • Homocysteine
  • Folic Acid