"In genotypic combination analysis considering PEMT -744GG/CHDH +432GG/BHMT +742GG as the reference combination PEMT -744GC/CHDH +432GG/BHMT +742GG genotypic combination was significantly higher in mothers of a down syndrome child compared with that in control mothers with an odds ratio of 2.061 (95% CI: 1.10-3.86 P=0.0342)."xsd:string