It is envisaged that if wild-type/mutant GCase can be refolded in the ER of humans, reducing ER stress and improving the trafficking of GCase to lysosomes, this will have important benefits not only for neuronopathic forms of GD (Type 2 and Type 3), for which no therapy is currently licensed, and PD patients with GBA mutations, but also sporadic forms of PD. This evidence concerns the gene GBA1 and Parkinson disease.