title: Mutation analysis of DARPP-32 as a candidate gene for schizophrenia.
abstract: Dopamine- and cAMP-regulated phosphoprotein of relative molecular mass 32kDa (DARPP-32) plays a pivotal role in the signal transduction of several neurotransmitters and neuromodulators that are implicated in the pathophysiology of a variety of neuropsychiatric disorders. A postmortem study reported a significantly reduced DARPP-32 expression in the dorsolateral prefrontal cortex (DLPFC) of patients with schizophrenia, suggesting possible involvement of DARPP-32 in the pathophysiology of schizophrenia. Hence, DARPP-32 was considered as a candidate gene for schizophrenia in this study. We first systemically searched for mutations in the DARPP-32 gene in 50 Han Chinese patients with schizophrenia from Taiwan. Five molecular variants were identified, including a C-to-G substitution (g.-2036C>G) in the putative core promoter that obliterated a predictive AP-2 transcription factor binding site, a G deletion in the untranslated exon 2 (g.1238delG), a G-to-A and an A-to-G substitutions in intron 2 (IVS2+31G>A) and intron 6 (IVS6+32A>G), respectively, and a three-base pair deletion of AGA in exon 6 that resulted in deletion of a glutamate at codon 135 (E135del). Further SNP- and haplotype-based association study in 249 patients and 273 control subjects, however, did not detect association of these markers with schizophrenia. Hence, our results suggest that the reduced DARPP-32 protein in patients with schizophrenia is unlikely caused by mutations in the DARPP-32 gene itself and the DARPP-32 gene is also unlikely a major susceptibility gene for schizophrenia. Nevertheless, the identification of these molecular variants should help the study of gene regulation and structure-function relationship of DARPP-32, and the association study of DARPP-32 gene with other neuropsychiatric disorders.
authors.affiliation: Department of Psychiatry, Tzu-Chi University and General Hospital, Hualien City, 970 Taiwan, ROC.
authors.forename: Chen-Hao
authors.initials: CH
authors.lastname: Li
authors.forename: Hsiao-Mei
authors.initials: HM
authors.lastname: Liao
authors.forename: Tsai-Wei
authors.initials: TW
authors.lastname: Hung
authors.forename: Chia-Hsiang
authors.initials: CH
authors.lastname: Chen
mesh_terms: D000483:Alleles; D001665:Binding Sites; D000242:Cyclic AMP / Q000235:genetics / Q000378:metabolism; D053938:DNA Fragmentation; D004252:DNA Mutational Analysis / Q000379:methods*; D017931:DNA Primers / Q000235:genetics; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D047668:Inteins / Q000235:genetics; D008297:Male; D008875:Middle Aged; D017354:Point Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012559:Schizophrenia / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D017931:DNA Primers; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D000242:Cyclic AMP