Defective HEXA causes GM2G1

Stable Identifier
Homo sapiens
Defective HEXA causes GM2-gangliosidosis 1
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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 alpha subunits are the cause of GM2-gangliosidosis type 1 (GM2G1) (MIM:272800), also known as Tay-Sachs disease (Okada & O'Brien 1969, Nakano et al. 1988). Classical Tay-Sachs disease is characterised by infant-onset neurodegeneration followed by paralysis, dementia and blindness, Death occurs by the age of 2 or 3 (Okada et al. 1971). The two other forms of Tay-Sachs disease, juvenile- and adult-onset, are less commom and severe than the infant-onset form (Suzuki et al. 1970, Johnson et al. 1982).
Literature References
PubMed ID Title Journal Year
5581981 Ganglioside GM2 storage diseases: hexosaminidase deficiencies in cultured fibroblasts

Leroy, J, O'Brien, JS, Veath, ML, Okada, S

Am. J. Hum. Genet. 1971
5793973 Tay-Sachs disease: generalized absence of a beta-D-N-acetylhexosaminidase component

O'Brien, JS, Okada, S

Science 1969
2970528 A point mutation in the coding sequence of the beta-hexosaminidase alpha gene results in defective processing of the enzyme protein in an unusual GM2-gangliosidosis variant

Ohno, K, Suzuki, K, Muscillo, M, Hoffman, AJ, Nakano, T

J Neurochem 1988
5460705 Juvenile GM2-gangliosidosis. Clinical variant of Tay-Sachs disease or a new disease

Suzuki, Y, Ishii, N, Rapin, I, Suzuki, K

Neurology 1970
6460466 Juvenile spinal muscular atrophy: a new hexosaminidase deficiency phenotype

Rowland, LP, Glaubiger, LM, Karp, HR, Wigger, HJ, Johnson, WG

Ann. Neurol. 1982
Name Identifier Synonyms
gangliosidosis GM1 DOID:3322 GM1 gangliosidosis (disorder), GM>1< gangliosidosis (disorder), beta-Galactosidase deficiency, deficiency of beta-galactosidase (disorder), Beta-galactosidase deficiency, Landing syndrome
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