GBA1 and Parkinson disease: The genetic heterogeneity of PD across populations highlights the need to identify additional population-specific risk variation, such as the novel intronic GBA1 variant in the African population 4, SV2C and WBSCR17 in East Asians, and HEATR6 in the Chinese population 29 in addition to the 12 potentially novel risk loci from a recent multi-ancestry GWAS meta-analysis on PD risk 6.