HEXB Gene (Hexosaminidase B)
Beta-hexosaminidase subunit beta; associated with Sandhoff disease and GM2 gangliosidosis
Gene Information Card
| Symbol | HEXB |
|---|---|
| Full Name | Hexosaminidase B (beta polypeptide) |
| Gene Type | Protein coding |
| Chromosomal Location | 5q13.3 |
| NCBI Gene ID | 3074 ncbi.nlm.nih.gov/gene/3074 |
| Ensembl ID | ENSG00000169862 |
| UniProt ID | P07686 |
| OMIM ID | 606873 |
| HGNC ID | 4879 |
| Aliases | HEX-B, ENC-1AS, beta-hexosaminidase subunit beta |
Description
The HEXB gene encodes the beta subunit of beta-hexosaminidase, a lysosomal enzyme that catalyzes the hydrolysis of GM2 gangliosides and other glycoconjugates. Together with the alpha subunit (HEXA), it forms the heterodimeric isoenzymes Hex A (alpha/beta) and Hex B (beta/beta). Mutations in HEXB cause Sandhoff disease, a severe lysosomal storage disorder characterized by accumulation of GM2 gangliosides, primarily in neurons.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Sandhoff disease (GM2-gangliosidosis type II) | Loss-of-function mutations in HEXB lead to deficiency of both Hex A and Hex B isoenzymes, causing GM2 ganglioside accumulation in lysosomes. | ClinVar, OMIM |
| GM2 gangliosidosis (variant 0) | Complete deficiency of beta-hexosaminidase activity due to biallelic HEXB mutations results in neuronal storage and neurodegeneration. | OMIM, NCBI |
| Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) | Rare association with HEXB mutations; mechanism unclear but linked to lysosomal dysfunction. | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 15.2 | Medium |
| Liver | 12.8 | Medium |
| Kidney | 10.5 | Medium |
| Lung | 8.3 | Low |
| Heart | 7.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 18.4 | High expression |
| HeLa | 14.2 | Medium expression |
| SH-SY5Y | 20.1 | High expression (neuronal) |
| HepG2 | 11.6 | Medium expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.850C>T (p.Arg284*) | Nonsense | <0.01% | Premature stop; loss of function |
| c.1510G>A (p.Gly504Ser) | Missense | <0.01% | Reduced enzyme activity |
| c.1A>G (p.Met1?) | Start loss | <0.01% | No protein synthesis |
| c.1214_1215del (p.Leu405fs) | Frameshift | <0.01% | Loss of function |
Mutation functional classification
Loss of Function (LOF)
Most HEXB mutations are loss-of-function, leading to deficiency of beta-hexosaminidase activity and GM2 accumulation.
Gain of Function (GOF)
No gain-of-function mutations reported for HEXB.
Dominant Negative (DN)
No dominant-negative effects described; disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • beta-N-acetylhexosaminidase activity (GO:0004563) | • lysosome (GO:0005764) |
| • ganglioside catabolic process (GO:0006689) | • hydrolase activity (GO:0016787) |
| • lysosomal lumen (GO:0043202) |
Pathways
• KEGG: hsa00511 - Other glycan degradation
• KEGG: hsa00604 - Glycosphingolipid biosynthesis - ganglio series
• Reactome: R-HSA-6798695 - Neutrophil degranulation
• Reactome: R-HSA-1660662 - Glycosphingolipid metabolism
Protein Summary
The HEXB protein (beta-hexosaminidase subunit beta) is a 556-amino acid lysosomal hydrolase that forms homodimers (Hex B) or heterodimers with the alpha subunit (Hex A). It cleaves terminal N-acetylglucosamine and N-acetylgalactosamine residues from glycoconjugates. Deficiency leads to Sandhoff disease.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| HEXB Knockout HEK293 Cell Line | EDJ-KQ13743 | Human | 3074 | Details Get a Quote |
| HEXB Knockout A-549 Cell Line | EDJ-KQ26275 | Human | 3074 | Details Get a Quote |
| HEXB Knockout HCT 116 Cell Line | EDJ-KQ43509 | Human | 3074 | Details Get a Quote |
| HEXB Knockout HeLa Cell Line | EDJ-KQ43510 | Human | 3074 | Details Get a Quote |
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