GBA1 and Gaucher disease: Homozygous mutations in the GBA gene that encodes for the lysosomal acid beta glucosidase (GBA1) cause the most common lysosomal storage disorder Gaucher disease (GD)1.Gaucher disease is a heterogeneous disease and is categorised by the absence (type I) or presence (types II and III) of the central nervous system involvement with GD II being the most severe2.