Currently, MTHFR C677T has been studied in relation to hypertension in 29 published papers indexed on the PubMed database, 25 of which were included in a meta-analysis conducted in 2007, which concluded that there was an overall association of MTHFR C677T with hypertension, with an OR of 1.343 (95%CI 1.198–1.505) [35]. This evidence concerns the gene MTHFR and hypertensive disorder.