Alcohol dehydrogenase 2 genotypes, maternal alcohol use, and infant outcome

Objective: To determine whether different alleles of the ADH2 gene (ADH2-1, ADH2-2 and ADH2-3) with differing levels of enzymatic activity can alter the risk of fetal alcohol effects. Study design: ADH2 genotypes were performed on 404 pregnant high-risk women and 139 infants as part of a larger study of alcohol use in pregnancy. Mothers were interviewed about alcohol use during pregnancy, and their infants were examined for alcohol-related features without knowledge of the exposure status. Results: The ADH2-1/3 genotype was more prevalent among black women (46%) than expected (33%); the rate among white women was low as expected (2%). More black women who reported high alcohol use during the pregnancy had the ADH2-1/3 genotype compared with those who reported no alcohol use (70% vs 44%). Sixty percent of the affected black infants had the ADH2-1/3 genotype compared with 29% of the unaffected infants (P < .045). The maternal genotype correlated with her chance of having an infant with alcohol-related physical features (odds ratio = 2.49). This association remained significant after accounting for confounders, such as smoking and maternal weight gain. Alcohol exposure was not significantly associated with infant outcome in black infants after accounting for genotype, smoking, and maternal weight gain, but this association could only be tested in 10 infants of mothers with high exposure. Conclusion: Women with the ADH2-1/3 genotype may be at greater risk for having an affected infant, which may be the result of greater ingestion of alcohol.