Folate metabolism and the risk of Down syndrome.

Folate is an important vitamin that contributes to cell division and growth and is therefore of particular importance during infancy and pregnancy. Folate deficiency has been associated with slowed growth, anaemia, weight loss, digestive disorders and some behavioural issues. Adequate folate intake around the time of conception and early pregnancy can reduce the risk of certain problems including neural tube defects. It has been suggested that certain versions (polymorphisms) of some genes can increase the risk of conceiving a baby with Down syndrome. If this is the case, then people with Down syndrome may be more likely to carry these forms of these genes and to experience associated problems in folate metabolism. Studies to date have found conflicting results, suggesting that these gene variants may be part of a more complex picture. In this issue, a further study reports no association between the presence of a common polymorphism of one of these genes and the risk of having a child with Down syndrome among mothers of Northern Indian origin. This article reviews these challenging findings and looks at where investigations can now go to resolve these issues.