For instance, Zhang et al. and Zhao et al. found that the ALDH2 rs671 and rs4767944 polymorphisms were associated with an increased risk of PD in the Chinese Han population (Zhang et al., 2015; Zhao et al., 2016); however, the association between ALDH2 rs4767944 polymorphism and PD was not observed in Iranian (Madadi et al., 2016). Here, ALDH2 is linked to Parkinson disease.