POSTER NO: 425

DDC and COMT genes in paranoid schizophrenia - an association study in Chinese

¹Yanbin Jia, ¹Qi Xu, ²Yanbo Yuan, ²Xin Yu, ¹Boyu Zhang, ¹Yubin Tao, ¹Ke Zou, ²Liang Shu, ²Yucun Shen, ¹Yan Shen
¹National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, CAMS and PUMC, 5 Dong Dan San Tiao,Beijing,100005,P.R.China, ²Institute of Mental Health, Peking University, 51 Hua Yuan Avenue,Haidian District, Beijing, 100083,P.R.China

Schizophrenia is one of the most common mental disorders with a lifetime risk of 0.5-1%. It is characterized by delusions, hallucinations and thought disorders . Family, twins and adoption studies suggest that 60-80% of susceptibility to schizophrenia can be attributed to genes. On the basis of the pharmacological activities of antipsychotic, schizophrenia has been considered to be associated with altered dopaminergic transmission. The genes of dopa decarboxylase (DDC) and catechol-O-methyltransferase (COMT) involved in dopaminergic metabolism, are often employed for candidate gene association studies of schizophrenia. In order to investigate the role of the DDC and COMT genes in paranoid schizophrenia, we genotyped 7 SNPs in the regulatory or coding regions of the DDC and COMT genes in this study. In the DDC gene, SNPs are rs930707(A/G), rs1451374(A/G) and rs6264(G/A, Met17Val) respectively. In the COMT gene, SNPs are rs1805052(C/G), rs740603(A/G), rs769224(A/G,Pro199Pro) and rs165656(C/G) respectively. ( http://ncbi.nlm.nih.gov/snp ).

82 unrelated patients with paranoid schizophrenia (34 males and 48 females, age 24.9 ± 5.9 years old) meeting ICD-10 diagnostic criteria and 108 matched controls (56 males and 52 females, age 25.8 ± 5.8 years old) were recruited. All subjects were Chinese and provided written informed consent. Each region containing SNPs was amplified by polymerase chain reaction (PCR), and then analyzed on 12% polyacrylamide gel after digestion with corresponding restriction enzyme. We compared the allele frequencies and genotypic distributions between patients and controls using the chi square analysis.

For rs930707(A/G) , rs6264(G/A, Met17Val), rs1805052 (C/G) and rs769224 (A/G, Pro199Pro), only one allele with G, G, C or A was respectively observed in all patients and controls. For rs1451374 (A/G), rs740603(A/G) and rs165656(C/G), no significant genotypic differences were found between controls and patients (rs1451374: chi square=3.40, df=2, p=0.183; rs740603: chi square =0.46, df=2,p=0.80; rs165656: chi square =2.75, df=2,p=0.25), and there were no significant differences in allelic frequencies between patients and controls.(rs1451374: chi square =2.93, df=1, p=0.09; rs740603: chi square =0.39, df=1,p=0.53; rs165656: chi square =0.43, df=1, p=0.51). This study may suggest that the 7 SNPs in the DDC and COMT genes do not play a major role in conferring susceptibility to paranoid schizophrenia. However, this study does not rule out the role of the DDC and COMT genes in paranoid schizophrenia. Further studies are required to assess the genetic association of the DDC and COMT gene polymorphisms with paranoid schizophrenia.