An adequate intake of folic acid during pregnancy, believed to protect against neural tube defects (NTDs) in babies, may also help prevent Down's syndrome, researchers report in The Lancet this week.
Scientists at Tel Aviv University and the Sheba Medical Centre in Israel, working with teams from Ukraine and the University of Leeds, UK, write that both NTD and Down's syndrome are seen in the same at-risk families and therefore taking folic acid supplements could be even more valuable than thought.
They compared medical data (maternal age, pregnancy outcome, congenital malformations, and karyotype) on around 490 families from Israel at high risk of NTD (445 with a history of NTD and 48 with isolated hydrocephalus) with data from 516 Ukrainian families at high risk of Down's syndrome.
In the families at risk of NTD, the number of pregnancies affected by Down's syndrome were much higher than expected - 11 cases compared to an expected 1·87, based on maternal age. In the families at risk of Down's syndrome, there were seven NTD pregnancies in 1847 pregnancies at risk, compared with 1·37 expected.
The report explains that there is evidence that some mothers of infants with Down's syndrome have abnormal metabolism of folate and methyl, as well as mutations in folate genes, features also seen in neural-tube defects. This is why Down's syndrome and NTD arise more often in the same family than would be expected from the incidence of each disorder considered separately.
The researchers write that they now have direct evidence of a link between Down's syndrome and NTD. This supports the theory that folate supplementation before conception has the potential to reduce both the frequency of Down's syndrome and NTD.
The B vitamin has also been implicated in promoting heart health in recent studies.