For example, analyses with rs10830963 (MTNR1B) revealed an interaction with rs2640666, an intronic variant downstream of MTRR. MTRR encodes 5-methyltetrahydrofolate-homocysteine methyltransferase reductase, implicated in metabolic syndrome [38] and epigenetic instability [39]. This evidence concerns the gene MTRR and metabolic syndrome.