MTHFR and hypertensive disorder: Indeed, genome-wide association studies have successfully identified several genetic variants linked to the development and the progression of HTN (Padmanabhan et al., 2008; Li et al., 2012), including methylenetetrahydrofolate reductase (MTHFR) gene variants, with rs1801133 being the most common and widely studied variant located in this gene (Xi et al., 2013; Fan et al., 2016).