The COMT L allele modifies the association between MAOB polymorphism and PD in Taiwanese

Objective: Reports suggest that catechol-O-methyltransferase (COMTL/L) (Val (158)/Met) and monoamine oxidase B (MAOB) intron 13 genotype polymorphism i s associated with PD. To understand the ethnicity-specific effects of genet ic polymorphism, we performed a case-control study of the association betwe en PD susceptibility and polymorphism of MAOB and COMT, both separately and in combination, in Taiwanese. Methods: Two hundred twenty-four patients wi th PD and 197 controls, matched for age, sex, and birthplace, were recruite d. MAOB and COMT polymorphism genotyping was performed by using PCR-based r estriction fragment length polymorphism (RFLP) analyses. chi (2), OR, and F isher's exact tests were used to compare differences in allelic frequencies and genotypes. Results: The MAOB G genotype (G in men and GIG in women) wa s associated with a 2.07-fold increased relative risk of PD. COMT polymorph ism, considered alone, showed no correlation with PD risk; however, a signi ficant synergistic enhancement was found in PD patients harboring both the COMTL and MAOB G genotypes. Conclusions: These results suggest that, in Tai wanese, PD risk is associated with MAOB G intron 13 polymorphism, and this association is augmented in the presence of the COMTL genotype, indicating an interaction of these two dopamine-metabolizing enzymes in the pathogenes is of sporadic PD. However, the relatively low frequencies of these combine d genotypes in our study necessitates confirmation with a larger sample siz e.