GBA1 and lysosomal storage disease: Homozygous mutations in the GBA gene cause Gaucher’s disease (GD), the most prevalent lysosomal storage disorder, due to deficiency of glucocerebrosidase activity, and the accumulation of its main substrate glucocerebroside (d-glucosyl-N-acylsphingosine, glucosylceramide) in lysosomes in macrophages (Barranger and Ginns 1989).