[Dopamine receptor gene (DRD2) polymorphism in patients with endogenous psychoses with regard to their clinical heterogeneity].
Recently an association between genetic dopamine receptor gene (DRD2) polymorphism and schizophrenia was observed in several studies. In the current investigation we attempted to undertake further study of such association using an extended sample which comprised patients with schizophrenia (n = 184), schizoaffective psychosis (n = 63), affective disorders (n = 121)); healthy control subjects (n = 117) and first-degree relatives of the patients with psychoses who show no signs of mental diseases (n = 111). The genotypes A1A1, A1A2 and A2A2 and the relationship between Taq1DRD2 variants and some clinical symptoms and pathogenetic features of the patients with schizophrenia were studied. The results did not confirm the association between DRD2 genotype and any of disorders studied. But the A2A2 genotype frequency in the schizophrenic patient's group, with illness duration above 20 years and highly expressed positive, negative and psychopathological symptoms, increased significantly as compared to control group (73.7% vs 52.9%) and patients with less illness duration (73.7% vs 42.5%). In the latter case odds ratio was calculated as 4.12. In the light of this finding, A2A2 DRD2 genotype appears to be related to chronicity of schizophrenia.