General maternal medication use, folic acid, the MDR1 C3435T polymorphism, and the risk of a child with a congenital heart defect.

Abstract

We sought to investigate maternal and child functional MDR1 C3435T polymorphism, periconception medication, folic acid use, and the risk of a congenital heart defect (CHD) in the offspring. MDR1 3435C>T genotyping was performed in 283 case triads (mother, father, child) and 308 control triads. Information on periconception medication and folic acid use was obtained through questionnaires. Mothers with MDR1 3435CT/TT genotype and using medication showed a significant association with the risk of a child with CHD (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.3-4.3) compared to mothers with MDR1 3435CC genotype not using medication. This risk increased without folic acid use (OR, 2.8; 95% CI, 1.2-6.4), and decreased in folic acid users (OR, 1.7; 95% CI, 0.8-3.7). Children carrying the MDR1 3435CT/TT genotype and periconceptionally exposed to medication without folic acid did not show significant risks. Mothers carrying the MDR1 3435T allele, using medication without folic acid, are at nearly 3-fold increased risk for CHD in the offspring.