ASSOCIATION STUDY OF SCHIZOPHRENIA AND THE DOPAMINE D3 RECEPTOR GENE LOCUS IN 2 INDEPENDENT SAMPLES

Using a case-control design, an association of schizophrenia with the dopamine D3 receptor gene (D3RG) locus was investigated. Initial analy sis of pooled results from published studies revealed a significant ex cess of individuals homozygous for either allele among the patients. T he association was next tested in two cohorts ascertained independentl y at Pittsburgh, Pennsylvania and at Houston, Texas. The Pittsburgh sa mple was comprised of patients with schizophrenia (DSM-III-R) (n = 130 ). The controls belonged to two groups: adults screened for the absenc e of substance abuse or major psychiatric illness (n = 128), and neona tes (n = 160). Multivariate analysis suggested an association with all ele 1 of the biallelic D3RG polymorphism in comparison with the adult, but not the neonatal, controls. The association was most marked among Caucasian patients with a family history of schizophrenia (odds ratio 13.69, confidence intervals 1.80, 104.30). Survival analysis suggeste d an earlier age of onset among male patients homozygous for allele 2. The Houston cohort included Caucasian patients with schizophrenia or schizoaffective disorder (DSM-III-R criteria, n = 50), and normal cont rols matched for gender (n = 51). In this group, no significant associ ations were noted among all the patients or among subgroups of patient s based on family history or age of onset. Possible reasons for the di scordant results are discussed. (C) 1996 Wiley-Liss, Inc.