We studied the relationship between schizophrenia and the DdeI polymorphism
in the 5' untranslated region (5'UTR) of the dopamine D1 receptor (DRD1) g
ene. This polymorphism is an A (Al allele) to G; (A2 allele) transition in
the 5' UTR of exon 2 at bp -48 (A-48G). One hundred forty-eight schizophren
ics and 148 control subjects were investigated. No significant differences
in genotypic counts and allele frequencies between schizophrenics and contr
ols were found. Although a significant difference between the patients clas
sified as disorganized type and the controls was discovered both in genotyp
ic counts and allele frequencies, neither association proved significant wh
en a Bonferroni correction was used. Moreover, there were no differences in
scores of main symptoms of schizophrenia based on the Manchester Scale bet
ween patients with A1/A1 genotype and those with. A1/A2 genotype. These fin
dings suggest that this gene may not be involved in the pathogenesis of sch
izophrenia. (C) 1999 Wiley-Liss, Inc.