The “thermolabile” variant of methylenetetrahydrofolate reductase and neural tube defects: an evaluation of genetic risk and the relative importance of the genotypes of the embryo and the mother. - Shields,D.C.; Kirke,P.N.; Mills,J.L.; Ramsbottom,D.; Molloy,A.M.; Burke,H.; Weir,D.G.; Scott,J.M.; Whitehead,A.S. (Am J Hum Genet, 1999)