GBA1 and Parkinson disease: The hypothesis of the gain of function in GCase theorizes that the mutant form of protein is recognized as misfolded, thus placing stress on mechanisms of protein degradation and interfering with α-synuclein breakdown and consequent endoplasmic reticulum stress, as observed in autophagy perturbations in cells derived from patients with GBA1-associated PD (Fernandes et al., 2016).