There is no association of tryptophan hydroxylase gene polymorphisms with schizophrenia and its leading symptomatology

Most of the symptoms of schizophrenia can be divided into two major categories: positive and negative. Unlike positive, negative symptoms are often irreversible and give evidence of profound mental impairment. Genes TPH1 and TPH2 of tryptophan hydroxylase, a key enzyme of serotonin biosynthesis, are considered as candidate genes predisposing to schizophrenia. Aim of the research is to study of the contribution of polymorphic variants of the TPH1 and TPH2 genes to the development of schizophrenia and the leading symptomatology of the disease in the Caucasian population of the Tomsk and Kemerovo regions. Subjects and Methods. 468 ethnically Russian patients with paranoid and simple schizophrenia are examined. DNA from venous blood is isolated by a phenol-chloroform micromethod. For the study, 3 polymorphic variants are selected in the TPH1 gene (rs1800532, rs7933505, rs684302) and 4 polymorphic variants in the TPH2 gene (rs7305115, rs4290270, rs1386494, rs1487278). Genotyping is carried out by “Real-time StepOnePlus” amplifier. The frequency distribution of the genotypes from the polymorphic loci examined is checked for compliance with the Hardy-Weinberg equilibrium using the %2 criterion. Differences are considered reliable at a significance level of p