Further evidence that hyperhomocysteinemia and methylenetetrahydrofolate reductase C677T and A1289C polymorphisms are not risk factors for schizophrenia

It has been suggested that total plasma homocysteine (tHcy) concentrations and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms are risk factors for schizophrenia. We conducted a case-control study to investigate whether tHcy levels and MTHFR C677T and A1298C variants are associated with schizophrenia, giving special consideration to confounding factors. Logistic regression analysis showed that neither tHcy nor MTHFR polymorphisms were associated with schizophrenia. Homozygosity for MTHFR C677T was associated with higher tHcy concentrations in control and schizophrenia groups (P < 0.0 1), which was mainly driven by the mate group. The A 1298C variant did not show any association with tHcy concentrations. In conclusion, these results do not confirm an independent relationship of tHey and MTHFR genotype with risk of schizophrenia. (c) 2005 Elsevier Inc. All rights reserved.