CYP2D6*4 polymorphism is not associated with Parkinson's disease and has no protective role against Alzheimer's disease in the Korean population.

CYP2D6*4 polymorphism is reported to be associated with Parkinson's disease (PD) and to have protective role against Alzheimer's disease (AD). Such findings are not extensively studied in the Oriental population, especially Koreans. The effects of CYP2D6*4 polymorphism on AD and PD were investigated by polymerase chain reaction-restriction fragment length polymorphism in Korean subjects. Heterozygous mutant allele was found in four of 93 patients with PD, 0 of 32 patients with AD and one of 121 control subjects (59 stroke, 59 normal controls and four other psychiatric disorders), but no homozygous mutant allele was found. There were no statistically significant differences between the AD group and controls, and between the PD group and controls. In conclusion, we suggest that CYP2D6*4 polymorphism does not confer susceptibility to PD in the Korean population. Also, due to such a rare occurrence of the CYP2D6*4 polymorphism, we can not confirm the protective role of the polymorphism against AD in the Korean population.