Polymorphisms of catechol-O-methyl transferase gene and dopamine transporter gene in dopamine metabolism system of patients with post-stroke depression

Abstract

Objective To investigate the association of post-stroke depression (PSD) with gene polymorphisms of catechol-O-methyl transferase (COMT) Val1 08/158Met and dopamine transporter 40bp variable number of tandem repeats (VNTR) in dopamine metabolism system. Methods Sixty-eight patients with PSD and 91 patients only suffered from stroke, admitted to our hospital from January 2010to June 2010, were chosen; the gene polymorphisms ofCOMT Val108/158Met and DAT 40 bp VNTR were analyzed by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results The genotypes of COMT gene amplifications were wild type (G/G),homozygous mutant type (A/A) and heterozygous type (A/G); 7 repeated genotypes (7/7, 9/7, 10/7, 10/9,10/10, 11/10 and 11/11) were noted in the DA T gene amplifications; frequencies of COMT alleles and genotypes were significantly different between the 2 groups (x2=5.703, P=0.017;x2=6.489, P=0.039). The frequencies of COMT alleles and genotypes were significantly different between the 2 female groups (x2=4.610, P=0.032;x2=6.547, P=0.024), but no significant differences were found between the 2 male groups (P＞0.05). The frequencies and heterozygosity of DAT alleles and genotypes showed no obvious differences between the 2 groups (P＞0.05). Conclusion The gene polymorphism of COMT Val108/158Met may be associated with PSD, while that of DAT 40bp VNTR is not. Key words: Dopamine; Depression; Catechol-O-methyl transferase; Dopamine transporter