Gene: HEXB
Alternate names for this Gene: ENC-1AS|HEL-248|HEL-S-111
Gene Summary: Hexosaminidase B is the beta subunit of the lysosomal enzyme beta-hexosaminidase that, together with the cofactor GM2 activator protein, catalyzes the degradation of the ganglioside GM2, and other molecules containing terminal N-acetyl hexosamines. Beta-hexosaminidase is composed of two subunits, alpha and beta, which are encoded by separate genes. Both beta-hexosaminidase alpha and beta subunits are members of family 20 of glycosyl hydrolases. Mutations in the alpha or beta subunit genes lead to an accumulation of GM2 ganglioside in neurons and neurodegenerative disorders termed the GM2 gangliosidoses. Beta subunit gene mutations lead to Sandhoff disease (GM2-gangliosidosis type II). Alternatively spliced transcript variants encoding different isoforms have been found for this gene.
Gene is located in Chromosome: 5
Location in Chromosome : 5q13.3
Description of this Gene: hexosaminidase subunit beta
Type of Gene: protein-coding
Gene: GFM2
Alternate names for this Gene: EF-G2mt|EFG2|MRRF2|MST027|MSTP027|RRF|RRF2|RRF2mt|hEFG2|mEF-G 2
Gene Summary: Eukaryotes contain two protein translational systems, one in the cytoplasm and one in the mitochondria. Mitochondrial translation is crucial for maintaining mitochondrial function and mutations in this system lead to a breakdown in the respiratory chain-oxidative phosphorylation system and to impaired maintenance of mitochondrial DNA. This gene encodes one of the mitochondrial translation elongation factors, which is a GTPase that plays a role at the termination of mitochondrial translation by mediating the disassembly of ribosomes from messenger RNA . Its role in the regulation of normal mitochondrial function and in disease states attributed to mitochondrial dysfunction is not known. Alternative splicing results in multiple transcript variants encoding distinct isoforms.
Gene is located in Chromosome: 5
Location in Chromosome : 5q13.3
Description of this Gene: GTP dependent ribosome recycling factor mitochondrial 2
Type of Gene: protein-coding
rs121907984 in
HEXB;GFM2 gene and
Sandhoff Disease
PMID 1720305 1991 Molecular basis of an adult form of beta-hexosaminidase B deficiency with motor neuron disease.
PMID 8950198 1996 Significance of two point mutations present in each HEXB allele of patients with adult GM2 gangliosidosis (Sandhoff disease) homozygosity for the Ile207-->Val substitution is not associated with a clinical or biochemical phenotype.
PMID 1531140 1992 A novel exon mutation in the human beta-hexosaminidase beta subunit gene affects 3' splice site selection.
PMID 9694901 1998 A Pro504 --> Ser substitution in the beta-subunit of beta-hexosaminidase A inhibits alpha-subunit hydrolysis of GM2 ganglioside, resulting in chronic Sandhoff disease.
PMID 9401004 1997 Molecular basis of heat labile hexosaminidase B among Jews and Arabs.
PMID 7633435 1995 A second, large deletion in the HEXB gene in a patient with infantile Sandhoff disease.
PMID 8357844 1993 Molecular basis of an adult form of Sandhoff disease: substitution of glutamine for arginine at position 505 of the beta-chain of beta-hexosaminidase results in a labile enzyme.
PMID 7557963 1995 A common beta hexosaminidase gene mutation in adult Sandhoff disease patients.
PMID 7626071 1995 A novel missense mutation (C522Y) is present in the beta-hexosaminidase beta-subunit gene of a Japanese patient with infantile Sandhoff disease.
PMID 9856491 1998 Two mutations remote from an exon/intron junction in the beta-hexosaminidase beta-subunit gene affect 3'-splice site selection and cause Sandhoff disease.