MTHFR and hypertensive disorder: Thus, this suggests that the interaction between age, gender, and the MTHFR (rs1801133) polymorphism in HTN may be partially due to their interactive effects on Hcy concentrations and DNA methylation status (Selhub et al., 1993; Kotchen, 2010; Kato et al., 2015; Liu et al., 2015; Fan et al., 2016).