GBA1 and Parkinson disease: We then attempted to replicate previously reported associations in TMEM175 and LRRK2 with GCase activity, by investigating these loci in a simplified meta-analysis using only age, sex, disease status, 10 PCs, and PD-relevant GBA1 SNPs including p.N370S, p.E326K, and p.T369M as covariates (Supplementary Fig. 3).