The present findings suggest that the MTHFRC677T polymorphisms are likely to be associated with the risk of developing BD and schizophrenia and influence the age at onset of BD but not the age at onset of schizophrenia.
In conclusion, the MTHFRC677T variant is unlikely to play a major role in the susceptibility to bipolar disorder, although MTHFR plays an important role in the one-carbon metabolism and DNA methylation.
Effect of the methylenetetrahydrofolate reductase gene polymorphisms on homocysteine, folate and vitamin B12 in patients with bipolar disorder and relatives.
The present Scandinavian results do not verify previous associations between the putative functional MTHFR gene polymorphisms and schizophrenia or bipolar disorder.
We were unable to confirm an association between bipolar disorder and C677T polymorphism (rs1801133) of the MTHFR gene, as suggested in some previous studies.
Functional deficiency, due to a common genetic variant of the methylenetetrahydrofolate reductase (NAD(P)H) (MTHFR) gene, could also affect the presentation of bipolar disorder.
A single base variant in MTHFR gene (C677T) results in the production of a mildly dysfunctional thermolabile enzyme and has recently been implicated in BD.
The authors performed a meta-analysis of studies examining the association between polymorphisms in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, including MTHFR C677T and A1298C, and common psychiatric disorders, including unipolar depression, anxiety disorders, bipolar disorder, and schizophrenia.
Effect of the methylenetetrahydrofolate reductase gene polymorphisms on homocysteine, folate and vitamin B12 in patients with bipolar disorder and relatives.
The authors performed a meta-analysis of studies examining the association between polymorphisms in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, including MTHFR C677T and A1298C, and common psychiatric disorders, including unipolar depression, anxiety disorders, bipolar disorder, and schizophrenia.
Because dopaminergic disturbance is thought to be involved in the development of bipolar disorder (BPD), it seems essential to investigate dopamine-related genes like the catechol-O-methyltransferase (COMT) gene, which are involved in dopamine metabolism, and the methylenetetrahydrofolate reductase (MTHFR) gene, which may affect COMT methylation and COMT function.
Functional deficiency, due to a common genetic variant of the methylenetetrahydrofolate reductase (NAD(P)H) (MTHFR) gene, could also affect the presentation of bipolar disorder.
Of the genes connected with homocysteine metabolism, some studies have found an association between polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene and bipolar disorder.
The present findings suggest that the MTHFR C677T polymorphisms are likely to be associated with the risk of developing BD and schizophrenia and influence the age at onset of BD but not the age at onset of schizophrenia.