NO EVIDENCE OF LINKAGE BETWEEN THE DOPAMINE D-2 RECEPTOR GENE AND SCHIZOPHRENIA

The antipsychotic effects of dopamine D-2 receptor antagonists (neurol eptics) and the psychotomimetic effects of dopamine agonists suggest t hat a defect of the D-2 receptor gene might be a factor in the etiolog y of schizophrenia. Fifteen families that contained several members su ffering from schizophrenia were tested for linkage between the D-2 rec eptor gene and schizophrenia. In addition, four flanking markers were tested. The mode of inheritance was assumed to be dominant. Five diffe rent models of the affection status, which ranged from a narrow to a b road definition of the affection status, were studied. Linkage analysi s was carried out with dominant, recessive, and intermediate modes of transmission. Two-point and multipoint analyses between schizophrenia and the D-2 receptor gene resulted in log-likelihood differences < -2 for all five models, and linkage between this candidate gene and schiz ophrenia was excluded. A mutation in the D-2 receptor gene itself is t herefore extremely unlikely to be related to a higher susceptibility t o schizophrenia, at least in the present group of families.