Sandhoff disease (SD) is a GM2 gangliosidosis (in the abbreviation GM2, G refers to ganglioside, the M is for monosialic, and 2 refers to the fact that it was the second monosialic ganglioside discovered) caused by mutations in the gene encoding the β subunit of β-hexosaminidase (HEXB), leading to a deficiency in the lysosomal enzymes β-hexosaminidase A (HEX A) and B (HEX B) [1]. Here, HEXB is linked to Salla disease.