Gene and Nutrient Etiologies of Human Heart Defects

Congenital heart defects are the most common type of birth defect; each year, more than 30,000 babies in the United States are born with this kind of abnormality. Conotruncal heart defects, considered to be a very serious type of defect, involve a structural abnormality in the chambers of the heart or blood vessels that lead to and from the heart. Infants born with conotruncal defects must undergo complex open heart surgery, and there is a high fatality rate. Folic acid supplementation during pregnancy has been shown to reduce the risk of conotruncal defects. However, some women who take folic acid during pregnancy still give birth to infants with conotruncal defects. Specific genes may influence the way individuals metabolize folic acid, and variations in these genes may make some infants more prone to developing heart defects. This study will examine the relationship between genes, maternal nutritional intake, and conotruncal heart defects. The results from this study may help to determine genetic and nutritional causes of congenital heart defects.

This study will use previously collected data on 550 infants born with conotruncal defects and 1060 infants born without heart defects. There will be no study visits specifically for this study. Infant DNA will be analyzed for genes that may play a role in folate metabolic pathways. Blood previously collected from the mothers during pregnancy will be analyzed for differences in nutrient intake. Specifically, levels of folic acid, choline, vitamin B12, and methionine will be examined.