[Association of allele polymorphism of dopamine d2 receptors with schizophrenic and affective disorders].

DRD2 Taq polymorphism has been studied in the samples from 214 patients (119 males, 95 females, mean age 37.8 +/- 13.6) and of 96 controls (50 males, 46 females, mean age 40.7 +/- 20.0). The latter group comprised 75 unrelated controls and 21 healthy first degree relatives of schizophrenic patients. All the patients were diagnosed according to ICD-10 and have been divided into 4 groups: paranoid schizophrenics (n = 102), schizotypic patients (n = 25), patients with schizoaffective psychoses (n = 40) and affective disorders (n = 47). Taq1A DRD2 polymorphism was represented by 3 genotypes: A1A1, A1A2, A2A2 (allele A2 was a result of nucleotide substitution). The frequencies of genotypes in affected group didn't significantly differ from a control one. However, a frequency of A2A2 genotype (0.45) in a group of paranoid schizophrenics was significantly higher, than in the patients with schizoaffective psychoses (0.22) or in a control group (0.26), but was similar to that of the patients with schizotypic or affective disorders (0.4). A2A2 DRD2 genotype seems to be a potential genetic factor of susceptibility to schizophrenia.