HOMOZYGOSITY AT THE DOPAMINE D3 RECEPTOR GENE IN SCHIZOPHRENIC-PATIENTS

Dopamine receptors have long been implicated in the etiology of schizo phrenia. It has been reported an association of schizophrenia with hom ozygosity at the dopamine D3 receptor gene locus. We have investigated the distribution of a D3 receptor gene polymorphism (BalI) in 107 sch izophrenic Spanish patients and 100 healthy matched controls. No stati stically significant differences between the patients and control grou p were detected with respect to either allele frequencies or genotype distribution. However, if not corrected for multiple testing, a correl ation was found between homozygosity and early age of onset of schizop hrenia (chi(2) = 3.1, df = 1, P = 0.03) and between Al allele frequenc y and disorganized and undifferentiated schizophrenia (chi(2) = 3.4, d f = 1, P = 0.03; chi(2) = 2.7, df = 1, P = 0.05, respectively). These results suggest the possibility that D3 polymorphisms may be among the physiological factors underlying schizophrenia; though not the determ ining factor. (C) 1996 Elsevier Science Ireland Ltd.