Definition:

Sandhoff disease is an autosomal recessive lysosomal storage disorder caused by mutations in HEXB that encodes beta-hexosaminidase subunit beta. Sandhoff disease is characterized by combined deficiency of hexosaminidase A (HexA) and hexosaminidase B (HexB) activities. GM2 ganglioside cannot be hydrolyzed and therefore accumulates primarily in neuronal tissues. This results in progressive neurologic degeneration. The severe form is characterized by an early age of onset and a rapidly progressive clinical course leading to death in early childhood, whereas the juvenile and adult forms start later and generally manifest a less severe course.