RESUMEN
Objective:To investigate the association between dopamine receptor D2(DRD2) polymorphisms and smoking in male patients with schizophrenia.Methods:Totally 773 patients with schizophrenia (567 smokers and 206 non-smokers) and 302 normal controls (168 smokers and 134 non-smokers) were recruited.The two single nucleotide polymorphisms (SNPs) (rs1800497 and rs1079597) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RELP).SHEsis genetic analysis platform was used to calculate linkage disequilibrium index and infer allele distribution and haplotype frequency.Results:There was no significant difference in two SNPs genotype and allele distributions between the patients and normal controls or between smokers and non-smokers in either patients or normal controls alone (Ps ＞ 0.05);the frequency estimations of haplotype C-A and T-G in patients with schizophrenia were higher than in normal controls (8.0％ vs.5.2％,10.2％ vs.4.1％,Ps ＜0.05),T-A (34.6％ vs.40.2％,P ＜0.05),whereas the frequency estimation of haplotype T-A in patients with schizophrenia was lower than in normal controls,and all the differences were statistically significant (34.6％ vs.40.2％,P ＜ 0.05).It was also observed that the frequency estimation of haplotype T-A in normal smokers was significantly lower than in normal non-smokers (2.5％ vs.6.1％,P ＜0.05).Conclusion:There may be a correlation between DRD2 polymorphisms and the susceptibility to schizophrenia,but not between DRD2 polymorphisms and smoking neither in patients with schizophrenia nor in normal controls.