Folic Acid and Down Syndrome

The investigation of families with a history of neural-tube birth defects, such as spina bifida and anencephaly, and those with a history of Down syndrome, suggests both may arise from a lack of folic acid.

Investigators embarked on the research project after previous studies suggested folic acid impacts the chromosomal abnormality known to cause Down’s. Since abnormal metabolism of folic acid has been established as a risk factor for neural-tube defects, researchers wondered if it might also play a role in Down’s.

The study involved about 490 families with a history of neural-tube defects and about 500 with a history of Down syndrome. The goal was to see if families with neural-tube defects also had more Down’s births than would be expected and vice versa.

An analysis of the families showed just that. Researchers found more than five-times the number of Down syndrome births in the families at high risk for neural-tube defect and a similar increased incidence of neural-tube defect births in the families at high risk for Down’s.

Study author Howard Cuckle concludes, “This study provides direct evidence of a link between Down syndrome and NTD. Folate supplementation before conception has the potential to reduce the frequency of Down syndrome.”

In an accompanying editorial, other scientists encourage caution before prescribing these supplements to prevent Down syndrome, noting the current study may have overestimated the connection. Still, they, too, believe it holds promise. The authors write, “...Although the report is somewhat provocative, it may well be the first epidemiological indication of the existence of a mechanism which could be used at a later stage in the primary prevention of Down syndrome.”

SOURCE: The Lancet, 2003;361:1331-1335,1316