title: Twelve-nucleotide repeat polymorphism of D4 dopamine receptor gene in Chinese familial schizophrenic patients.
abstract: BACKGROUND
  Disturbances in dopaminergic transmission have been implicated in the etiology of schizophrenia. Catalano et al reported an association between delusional disorder and the number of a 12-nucleotide (bp) repeat sequence in the first exon of dopamine D4 receptor gene (DRD4), which indicated a possible role of this polymorphism in the pathogenesis of psychotic disorders.
  
  
  METHODS
  DNA of 42 Chinese controls, 50 sporadic schizophrenic patients, and 30 familial schizophrenic probands were collected. Genotype of the 12-bp repeat polymorphism of DRD4 was determined with polymerase chain reaction and agarose gel electrophoresis. Genotypic and allelic frequencies were compared among the three groups using the chi-square test.
  
  
  RESULTS
  Forty-three (86%) sporadic schizophrenic patients, 25 (83.3%) familial schizophrenic probands, and 35 (83.3%) controls were A1 (two 12-bp repeat) homozygotes. One (2.0%) sporadic schizophrenic and 1 familial schizophrenic patient were A2 (one 12-bp repeat) homozygotes. There was no significant difference in allelic and genotypic distributions among the three groups.
  
  
  CONCLUSIONS
  The present data do not support an association between schizophrenia and any specific allele of the 12-bp repeat polymorphism of DRD4. Significance of familial/sporadic division of schizophrenia cannot be supported regarding this repeat polymorphism.
authors.affiliation: Department of Psychiatry, Veterans General Hospital-Taipei, Taiwan, R.O.C.
authors.forename: C J
authors.initials: CJ
authors.lastname: Hong
authors.forename: H J
authors.initials: HJ
authors.lastname: Chiu
authors.forename: Y S
authors.initials: YS
authors.lastname: Chang
authors.forename: C B
authors.initials: CB
authors.lastname: Sim
mesh_terms: D000328:Adult; D000483:Alleles; D002681:China; D004247:DNA / Q000032:analysis / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D012559:Schizophrenia / Q000235:genetics*
chemical_list: C493599:DRD4 protein, human; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4; D004247:DNA