GLB1 and GM1 gangliosidosis: GM1 gangliosidosis (MIM# 230500) is a lysosomal storage disorder (LSD) caused by the deficiency of lysosomal β-galactosidase (β-Gal; GLB1; E.C. 3.2.1.23), an enzyme deputed to the hydrolysis of the terminal β-galactosyl residues from GM1 ganglioside, glycoproteins, and glycosaminoglycans, such as keratan-sulfate [1].