Genetic polymorphism of methylenetetrahy-drofolate reductase (MTHFR) 677C>T in patients with schizophrenia: case-control study in Nizhegorodsky region of Russia

Background. A number of studies demonstrated that disturbances of folate metabolism, including genetic polymorphism MTHFR 677C>T, are more common in patients with schizophrenia than in the general population. Some studies have shown that carriage of the polymorphism MTHFR 677C>T in patients with schizophrenia is associated with the male gender. However, the results obtained in different geographical areas and ethnic groups differ significantly. In Russia such studies have not been conducted to date. The objective of this study was to investigate the association of genetic polymorphism MTHFR 677C>T with schizophrenia, as well as with gender and age of patients in Nizhegorodsky Region of Russia by comparison with the control group (healthy blood donors). Methods. 150 patients diagnosed with schizophrenia and 150 healthy blood donors, comparable to patients in age and gender, were examined for the carriage of polymorphism MTHFR677C>T using PCR method. Results. The carriage of genetic polymorphism MTHFR 677C>T is more common among patients with schizophrenia than in healthy donors, but not significantly at the available number of observations (р=0.488; OR=1.205; 95% CI=0.766-1.897). The carriage of this polymorphism in male patients (n=75) is more common than in female patients (n=75, р=0.51) and male donors (n=75, р=0.32; OR=1.454, 95% CI=0.765-2.766), but also not significant. However, there were significant differences in carriage frequencies of the studied polymorphism between patients of the age group over 50 years and healthy donors of the age group over 50 years (oR=2.424, 95% CI=1.047-5.612), and also between patients of the age group over 50 years and patients of the age group less than 30 years (р=0.021). It was also found that the average age of patients with genotypes CT, TT and T allele of gene MTHFR677 is significantly higher than in patients with normal genotype CC (p=0.036), which is not observed in the group of healthy donors (p>0.05). The results suggest the need for further study of genetic polymorphism MTHFR677C>T as a risk factor for schizophrenia in representatives of the Russian population, especially over the age of 30 years