Research paper
Dopamine D3 receptor Gly9/Ser9 polymorphism and schizophrenia: no increased frequency of homozygosity in German familial cases

https://doi.org/10.1016/0920-9964(95)00074-7Get rights and content

Abstract

Disturbances in the dopaminergic transmission have been implicated in the etiology of schizophrenia. Recently, an association of schizophrenia with increased homozygosity of a Gly9/Ser9 polymorphism in the dopamine D3 receptor gene (DRD3) has been reported (Crocq et al., 1992; Mant et al., 1994). This finding reflected a departure from the Hardy-Weinberg equilibrium in the genotype distribution observed in schizophrenic patients. The effect was found to be at its strongest in patients with a high familial loading. In the present study, we tried to replicate this finding in a sample of 146 German patients with a DSM-III-R diagnosis of schizophrenia. All patients had a positive family history of major psychiatric disorder including 70 patients with a family history of schizophrenia. Given our sample size, we have a power of 99.8% to detect a deviation from the Hardy-Weinberg equilibrium of the reported magnitude. However, we found no evidence of an excess of homozygosity in our schizophrenic patients. This seems to indicate that homozygosity for the Gly9/Ser9 polymorphism at the DRD3 locus is unlikely to confer susceptibility to schizophrenia in the German population. This held true whether the psychiatric diagnoses in the affected relatives of the patient samples was established by the family history or family interview method.

References (24)

  • C. Laurent et al.

    Homozygosity at the dopamine D3 receptor locus is not associated with schizophrenia

    J. Med. Genet.

    (1994)
  • F. Macciardi et al.

    An association study between schizophrenia and the dopamine receptor genes DRD3 and DRD4 using haplotype relative risk

    Hum. Hered.

    (1994)
  • Cited by (22)

    View all citing articles on Scopus
    View full text