Cholinergic receptor nicotinic beta 3 subunit polymorphisms and smoking in male Chinese patients with schizophrenia.

Objective The aim of this study was to examine if cholinergic receptor nicotinic beta 3 subunit (CHRNB3) was a common genetic basis for both nicotine dependence and schizophrenia. Methods Two CHRNB3 promoter single nucleotide polymorphisms (SNPs) were genotyped in 773 patients with schizophrenia and 302 healthy volunteers. Associations between smoking, schizophrenia, smoking+schizophrenia and CHRNB3 were analyzed. The mRNA expression of CHRNB3 in human brains was examined, and the expression correlations between CHRNB3 and dopaminergic and GABAergic receptor genes were evaluated. Results The association between CHRNB3 and smoking was significant in the total sample, less significant in the smoking with schizophrenia, and suggestive in the smoking without schizophrenia. CHRNB3 had significant mRNA expression that was correlated with dopaminergic or GABAergic receptor expression in human brains. The two CHRNB3 SNPs had significant cis-acting regulatory effects on CHRNB3 mRNA expression. Conclusions Risk for smoking behavior was associated with CHRNB3. CHRNB3 mRNA is abundant in human brain and could play important role in the pathogenesis of smoking behavior.