Defective HEXB causes GM2G2

Stable Identifier
Homo sapiens
Defective HEXB causes GM2-gangliosidosis 2
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Beta-hexosaminidase (HEX) cleaves the terminal N-acetyl galactosamine (GalNAc) from glycosaminoglycans (GAGs) and any other molecules containing a terminal GalNAc. There are two forms of HEX; HEXA and B. The A form is a trimer of the subunits alpha, beta A and beta B. The B form is a tetramer of 2 beta A and 2 beta B subunits (O'Dowd et al. 1988). Defects in the two subunits cause lysosomal storage diseases marked by the accumulation of GM2 gangliosides in neuronal cells.

Defects in the beta subunits are the cause of GM2-gangliosidosis type 2 (GM2G2; MIM:268800), also known as Sandhoff disease (Sandhoff et al. 1968, Banerjee et al. 1991). Sandhoff disease is an autosomal recessive lysosomal storage disease clinically indistinguishable from GM2-gangliosidosis type 1, presenting early blindness with cherry-red spots on the macula, progressive motor and mental deterioration and macrocephaly. Death usually occurs by the age of 3 years.

Literature References
PubMed ID Title Journal Year
1720305 Molecular basis of an adult form of beta-hexosaminidase B deficiency with motor neuron disease

Boyers, MJ, Siciliano, L, Banerjee, P, Oliveri, D, Horwitz, AL, Li, SC, McCabe, NR, Dawson, G

Biochem Biophys Res Commun 1991
5651108 Deficient hexozaminidase activity in an exceptional case of Tay-Sachs disease with additional storage of kidney globoside in visceral organs

Jatzkewitz, H, Andreae, U, Sandhoff, K

Life Sci. 1968
Name Identifier Synonyms
gangliosidosis GM2 DOID:3321 GM>2< gangliosidosis (disorder)
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