This study aimed to determine the role of FMR1 gene CGG repeat expansions in PD patients from the Chinese population, and we investigated the size of FMR1 CGG repeat expansions in a large Chinese cohort of patients with PD and healthy controls by RP-PCR and fluorescent PCR, including 2,362 patients and 1,072 controls from the Chinese mainland. This evidence concerns the gene FMR1 and Parkinson disease.