We were unable to confirm an association between bipolar disorder and C677T polymorphism (rs1801133) of the MTHFR gene, as suggested in some previous studies.
We investigated the effect of polymorphic variants of c.1298A>C (Glu429Ala) and c.677C>T (Ala222Val) in methylenetetrahydrofolate (MTHFR) gene on the total homocysteine (tHcy), folate and B12 levels in patients with bipolar disorder, first-degree relatives of patients, and controls.