Genetic study of dopamine D1, D2, and D4 receptors in schizophrenia.

The goal of this study was to define precisely the involvement of the dopamine D1, D2, and D4 receptor genes in the etiology of schizophrenia. A linkage analysis using the lod score method was performed in 37 families originating from France (n = 14) and from the Island of La Réunion in the Indian Ocean (n = 23). No evidence of linkage between schizophrenia and genetic markers located at these loci was found. A simulation study was carried out to gauge the significance of these results. The conclusions of a nonparametric linkage test (i.e., the affected pedigree member method) were equally negative. For each genetic marker, an allelic association with the disease was also sought: 80 unrelated patients and 80 healthy control subjects were tested, and no significant association was found. These results, which are in agreement with those obtained by other groups, do not support the involvement of the dopamine D1, D2, and D4 receptor genes in the pathogenesis of schizophrenia.