As reviewed elsewhere (40), the available evidence from meta-analyses of clinical studies indicates that the MTHFR 677C→T polymorphism is associated with an increased risk of hypertension and hypertension in pregnancy by up to 87% (41, 55, 56), with reported ORs from meta-analyses ranging from 1.36 (95% CI: 1.20, 1.53) to 1.87 (95% CI: 1.31, 2.68), for worldwide and Chinese populations, respectively (41, 57, 58). This evidence concerns the gene MTHFR and hypertensive disorder.