engleski

Methylenetetrahydrofolate reductase (MTHFR) C677T mutation association with schizophrenia and depression

Schizophrenia clinical phenotype is heterogeneous entity with respect to response to medication and clinical outcome. It is also possibly influenced by genetic heterogeneity. T677 allele encodes for a thermolabile enzyme associated with hyperhomocysteinemia if present in homozygous genotype, and is a common missense mutation (C677T) of the methylenetetrahydrofolate reductase (MTHFR) gene. It has been reported to be associated with schizophrenia, depression and bipolar disorder (Arinami et al.). Aim of our study was to estimate frequencies of the C677T mutant alleles and genotypes and to determine possible association of mutated allele with schizophrenia and depression. We compared a group of 69 patients with schizophrenia (diagnosed as F20 and F25 according to International Classification of the Disease - ICD 10), 46 depression patients (F33) and a group of 111 healthy volunteers, with regard to MTHFR allelic and genotype frequency. Among 111 healthy controls, C677T genotype frequencies were as follows: 51.4% C/C, 47.7% C/T and 0.9% T/T, while allelic frequencies of C and T alleles were 75.2% and 24.8%, respectively. In schizophrenia group of patients, genotype frequencies for the C/C, C/T and T/T were 53.6%, 36.2%, and 10.1%, respectively. In depression group there were 43.5% C/C, 47.8% C/T and 8.7% T/T. Allelic frequencies of C and T alleles in schizophrenia was 71.7% and 28.3% while the C and T frequency in depression was 67.4% and 32.6% respectively. Genotype frequencies between schizophrenia and healthy subjects differed significantly (P=0.009 - Chi square test), what emerges from the difference for the T/T genotypes (P=0.011; Z-test), and value of the T/T odds ratio (OR= 12.42; 95%CI 2.28-67.46). Somewhat lower level of significance was observed among depression patients (P=0.037 - Chi square test, P=0.042 - T/T genotype Z-test, and T/T odds ratio (OR= 10.48; 95%CI 1.69-64.95), compared to controls. Our preliminary results strongly suggest that MTHFR gene homozygosity could be involved in the pathogenesis of schizophrenia and probably in somewhat smaller extent is linked to pathogenesis of depression.

MTHFR; schizophrenia; depression

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