Differences between GM1 gangliosidosis and Morquio B disease can be attributed to a lower affinity and activity of β-galactosidase variants towards substrates with Gal-β1,4-GlcNAc motifs in Morquio patients compared to the Gal-β1,3-GalNAc motive present in ganglioside GM1 [301]. This evidence concerns the gene GAL and GM1 gangliosidosis.