Family association study between DRD2 and DRD3 gene polymorphisms and schizophrenia in a Portuguese population

Ambrósio, Alda M; Kennedy, James L; Macciardi, Fabio; Macedo, António; Valente, José; Dourado, Ana; Oliveira, Catarina R; Pato, Carlos

doi:10.1016/j.psychres.2003.12.016

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Volume 125, Issue 3 , Pages 185-191, 15 March 2004

Family association study between DRD2 and DRD3 gene polymorphisms and schizophrenia in a Portuguese population

Alda M Ambrósio
- Department of Neurochemistry, Faculty of Medicine, Center for Neuroscience of Coimbra, University of Coimbra, 3004-517 Coimbra, Portugal
- Corresponding author. Tel.: +351-239-820190; fax: +351-239-822776
James L Kennedy
- Neurogenetics Section, Center for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
Fabio Macciardi
- Neurogenetics Section, Center for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
António Macedo
- Department of Psychological Medicine, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
José Valente
- Department of Psychological Medicine, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
Ana Dourado
- Department of Psychological Medicine, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
Catarina R Oliveira
- Department of Neurochemistry, Faculty of Medicine, Center for Neuroscience of Coimbra, University of Coimbra, 3004-517 Coimbra, Portugal
Carlos Pato
- Center for Psychiatric and Molecular Genetics, SUNY Upstate Medical University and Behavioral Health Care Line, VISN 2, Veterans Administration, Syracuse, NY, USA

Received 27 February 2003; received in revised form 23 September 2003; accepted 22 December 2003.

Abstract

Schizophrenia is a highly heritable condition, as demonstrated in family, twin and adoption studies. Candidate genes from the dopaminergic system have long been hypothesized to be involved in the etiology of this disorder. In the present study, we investigated the genetic association between polymorphisms in the D2 and D3 dopamine receptor (DRD2, DRD3) genes and schizophrenia. We examined 90 trios from Portugal, and negative results were obtained from association studies with both Haplotype Relative Risk (HRR) and Transmission Disequilibrium Test (TDT), as well as TRANSMIT. Therefore, we conclude that neither the DRD2 nor the DRD3 gene polymorphisms investigated are associated with schizophrenia in our sample.

Keywords: Schizophrenia, Association study, Candidate genes, Linkage disequilibrium, Haplotypes