c677t methylenetetrahydrofolate reductase (mthfr) gene polymorphism in schizophrenia and bipolar disorder: an association study in iranian population.

objective: the methylenetetrahydrofolate reductase (mthfr) gene polymorphism c677t is suspected to be a risk factor for psychiatric disorders, but it remains inconclusive whether the mthfr polymorphism c677t is imputed to vulnerability to schizophrenia and bipolar disorder. method: we prompted impetus to appraise this polymorphism in an iranian population. therefore, 90 patients with bipolar disorder type i (bid), 66 patients with schizophrenia diagnosed according to dsm-iv criteria, and 94 unrelated controls with no history of psychiatric disorders were recruited for this study. genotype distribution and allelic frequencies of c677t polymorphism were investigated. results: we found no robust differences between patients with bid and schizophrenia with control participants either for allele frequencies or genotype distribution of mthfr c677t polymorphism. however, a trend toward an increased risk for t allele was observed in the bid patients [with odds ratio (or) of 1.28(ci 95%: 0.8-1.31), p>0.05]. conclusion: however, the present and some previous studies failed to elucidate possible interaction between mthfr c677t polymorphism and vulnerability to schizophrenia and bipolar disorder; still some associations have been revealed in performed meta-analyses that warrant further studies.