Qin Xiao, Yiwei Qian, Jiujiang Liu, Shaoqing Xu, and Xiaodong Yang,
Roles of functional catechol-O-methyltransferase genotypes in Chinese patients with Parkinson’s disease

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5405521/

The study shows possible association of PD with COMT rs4680 (A) allele (low enzymatic activity) in an Asian population.