Interaction of PDGFRA Promoter Haplotypes and Maternal Environmental Exposures in the Risk of Spina Bifida

BACKGROUND: Neural tube defects are multifactorial malformations involving both environmental exposures, such as maternal nutrition, and genetic factors. Aberrant expression of the platelet-derived growth factor alpha-receptor (PDGFRA) gene has been implicated in neural-tube-defect etiology in both mice and humans. METHODS: We investigated possible interactions between the PDGFRA promoter haplotype of mother and child, as well as maternal glucose, myo-inositol, and zinc levels, in relation to spina bifida offspring. Distributions were determined of the PDGFRA promoter haplotypes H1 and H2 in a Dutch cohort, consisting of 88 spina bifida children with 56 of their mothers, and 74 control children with 72 of their mothers, as well as maternal plasma glucose, myo-inositol, and red blood cell zinc concentrations. RESULTS: A significantly higher frequency of H1 was observed in children with spina bifida than in controls (30.1 vs. 203%; OR = 1.69, 95% CI 1.02-2.83). High maternal body mass index (BMI) and glucose were significant risk factors for both H1 and H2 children, whereas low myo-inositol and zinc were risk factors for H2 but not for H1 children. Stepwise multiple logistic regression analysis showed that high maternal glucose and low myo-inositol are the main risk factors for H2 spina bifida children, whereas for H1 spina bifida children, maternal BMI was the main risk factor. Interestingly, H1 mothers (median 165.5 cm) showed a significantly lower body height than H2 mothers (median 169.1 cm; p = 0.003). CONCLUSIONS: These data suggest that the child's PDGFRA promoter haplotype is differentially sensitive for periconceptional exposure to glucose, myo-inositol, and zinc in the risk of spina bifida. Birth Defects Research (Part A) 85:629-636, 2009. (C) 2009 Wiley-Liss, Inc.