Molecular genetic study of clinical and cognitive features of schizophrenia: No associations with genes SOD2, GSTO1, NQO1

Abstract

 The main features of schizophrenia are characterized by three domains of symptoms, including positive symptoms, negative symptoms, and cognitive defi cits, the overlap of which forms a polymorphism of clinical manifestations. Previous molecular genetic studies have found signifi cant genetic overlaps between the cognitive abilities and the risk of schizophrenia developing. Recent evidence suggests that oxidative stress may play an important role in the pathophysiology of schizophrenia.Aim. The aim of the study was to investigate the associations of polymorphisms of genes encoding the antioxidant enzymes SOD2, GSTO1, and NQO1 with clinical polymorphism of schizophrenia and the severity of cognitive deficit.Material and Methods. A comprehensive examination of 457 patients with a diagnosis of schizophrenia was carried out. Out of the total group of examined patients, cognitive functions were assessed using the BACS scale in 150 schizophrenic patients. The control group comprised 135 healthy individuals with age and gender corresponding to patient group. Their cognitive function was assessed. Genotyping of SOD2 (rs4880), GSTO1 (rs4925), and NQO1 (rs1800566) was done by realtime PCR.Results. When analyzing the distribution of genotypes and alleles of polymorphic variants of genes encoding the antioxidant enzymes SOD2, GSTO1, and NQO1, no associations between the studied loci and schizophrenia in the Russian population of the Siberian region were revealed. Also, no associations were found with clinical polymorphism of disease (disease course type, leading symptoms (positive or negative), and age of disease onset). The cognitive abilities of schizophrenic patients and healthy individuals were diff erent as expected, but no associations with genetic characteristics were found.Conclusion. In this work, we obtained negative results in regard to associations of polymorphic variants of genes encoding the antioxidant enzymes SOD2 (rs4880), GSTO1 (rs4925), and NQO1 (rs1800566) with the development of schizophrenia in the Russian population in the Siberian region, as well as with the severity of cognitive defi cit. The genetic profi le for the studied loci did not aff ect the clinical manifestations of disease in the examined sample.