Disequilibrium transmission of Ser9Gly polymorphism of dopamine D_(3) receptor gene in 151 schizophrenia families

Objective: To investigate the association between Ser9Gly polymorphism of dopamine D 3 receptor gene (DRD3) and schizophrenia. Methods: The Ser9Gly polymorphism of DRD3 was tested in 151 Chinese Han's pedigrees each of which had two or more affected schizophrenia siblings who fulfilled the ICD 10 criteria with the parents alive and at most only one of whose parents may have the history of suffering schizophrenia. Results: (1) Totally, the distributions of alleles or genotypes of DRD3 Ser9Gly polymorphism are not significantly different between the groups of parents, unaffected siblings and affected siblings, and between the sub types of schizophrenia. (2) The transmission disequilibrium test (TDT) shows the transmission disequilibrium in affected siblings (χ 2 = 7.76, P = 0.005 3, OR = 1.70, 95%IC: 1.15 2.52). (3) The correlation analysis was taken between genotypes and clinical status. The results show that schizophrenia siblings with Ser9 allele are apt to have negative symptoms. Conclusion: The results show that there may exist association between DRD3 and schizophrenia. This research supports that DRD3 may be one of the candidate genes of schizophrenia.