Further association study on dopamine D2 receptor variant S311C in schizophrenia and affective disorders

The dopamine D2 receptor gene is a candidate gene for schizophrenia because the potency of certain neuroleptics correlates with their affinity for this receptor. Case-control studies in 291 schizophrenics, 78 patients with affective disorders, and 579 controls on an association of a molecular variant of S311C of the dopamine D2 receptor with psychiatric disorders were conducted. The frequency of individuals with S311C was significantly higher in schizophrenics with the absence of negative symptoms (17.1%, P < 0.00001), but similar in schizophrenics with the presence of negative symptoms (5.7%, P = 0.46) when compared with the controls (4.1%). The frequency of S311C was significantly higher in familial schizophrenics from one local area but not in those from other areas. It was significant that S311C was frequently present in patients with mood-incongruent psychotic affective disorders (33.3%, P < 0.0001), but not in those with other affective disorders. These data suggest that S311C might be one of the genetic factors for symptomatic dimensions of delusions and hallucinations and might be involved in underlying clinical heterogeneity in schizophrenia and affective disorders.