The HhaI polymorphism in the CYP2D6 gene is not associated with Parkinson's disease in a Caucasian population

Polymorphisms of the CYP2D6 gene have been reported in association with susceptibility to Parkinson's disease (PD). In a Japanese population, a HhaI polymorphism in the CYP2D6 gene was associated with a 5.56‐fold risk of PD (Tsuneoka et al., 1993). We investigated the frequency of this polymorphism in Caucasian patients with sporadic PD and in healthy controls. Although the frequency of the polymorphism was significantly higher in Caucasians compared with Japanese, there was no association with PD.