GBA1 and Parkinson disease: Compared with skin fibroblasts from a healthy individual (normal) or patients with parkinsonism, Gaucher’s disease, or PD linked to mutations in the GBA or LRKK2 gene, the 3XSNCA fibroblasts displayed between 1.7- and 2.1-fold increase in α-synuclein abundance (Fig. 4A).