GBA1 and Parkinson disease: Interestingly, a moderate mRNA upregulation for the lysosomal enzyme glucocerebrosidase (GBA; log2 fold change=0.31) was notable in the PARK4 blood RNA-seq GSEA; GBA is known to contribute to SNCA degradation, and its mutations act as modifiers of PD risk (Yap et al., 2011; Sidransky and Lopez, 2012; Fishbein et al., 2014).