In addition, both MTHFR C677T and A1298C polymorphisms have been linked to an increased risk of chromosome malsegregation in lymphocytes of mothers of DS children.[15] Following the original study by James and coworkers,[6] several investigators performed case–control studies to evaluate MTHFR C677T and/or A1298C polymorphisms as maternal risk factors for the birth of a child with DS, but the small sample-size of these studies coupled to differences in allele frequencies, lifestyles and dietary habits among different populations, yielded conflicting results.[15–22]. The gene discussed is MTHFR; the disease is Dravet syndrome.