B3GALNT2: Beta-1,3-N-Acetylgalactosaminyltransferase 2
A key enzyme in O-mannosylation, associated with congenital muscular dystrophy and brain malformations.
Gene Information Card
| Symbol | B3GALNT2 |
|---|---|
| Full Name | Beta-1,3-N-Acetylgalactosaminyltransferase 2 |
| Gene Type | Protein coding |
| Chromosomal Location | 1q42.3 |
| NCBI Gene ID | 148789 ncbi.nlm.nih.gov/gene/148789 |
| Ensembl ID | ENSG00000162849 |
| UniProt ID | Q8NCR0 |
| OMIM ID | 610194 |
| HGNC ID | 28596 |
| Aliases | B3GALNT2, B3GalNAc-T2, MDDGA11, MEB |
Description
The B3GALNT2 gene encodes beta-1,3-N-acetylgalactosaminyltransferase 2, a Golgi enzyme that transfers N-acetylgalactosamine (GalNAc) to O-mannose glycans on alpha-dystroglycan. This modification is essential for the proper function of dystroglycan as a receptor for extracellular matrix proteins. Mutations in B3GALNT2 cause a form of congenital muscular dystrophy with brain malformations, classified as dystroglycanopathy type A11 (MDDGA11) or muscle-eye-brain disease (MEB).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies) type A, 11 (MDDGA11) | Loss-of-function mutations in B3GALNT2 impair O-mannosylation of alpha-dystroglycan, disrupting its binding to laminin and other extracellular matrix proteins, leading to muscle degeneration and brain malformations. | OMIM #615181, ClinVar |
| Muscle-eye-brain disease (MEB) | Similar mechanism as MDDGA11; B3GALNT2 mutations reduce or abolish enzyme activity, causing defective glycosylation of alpha-dystroglycan. | OMIM #253280, ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.8 | Low |
| Heart | 8.5 | Low |
| Skeletal Muscle | 7.2 | Low |
| Kidney | 6.1 | Low |
| Liver | 4.3 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 15.2 | Embryonic kidney cells |
| SH-SY5Y | 10.5 | Neuroblastoma cells |
| HepG2 | 5.8 | Hepatocellular carcinoma cells |
| A549 | 4.1 | Lung carcinoma cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | Rare | Loss of start codon, likely loss of function |
| c.632C>T (p.Thr211Met) | Missense | Rare | Reduced enzyme activity |
| c.859G>A (p.Gly287Arg) | Missense | Rare | Impaired protein folding and activity |
| c.1003C>T (p.Arg335*) | Nonsense | Rare | Premature stop, loss of function |
Mutation functional classification
Loss of Function (LOF)
Most reported B3GALNT2 mutations are loss-of-function, leading to reduced or absent enzyme activity and defective alpha-dystroglycan glycosylation.
Gain of Function (GOF)
No gain-of-function mutations have been reported for B3GALNT2.
Dominant Negative (DN)
No dominant-negative mutations have been described; the disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • acetylgalactosaminyltransferase activity (GO:0008376) | • Golgi apparatus (GO:0005794) |
| • Golgi membrane (GO:0000139) | • glycosyltransferase activity (GO:0016757) |
| • protein glycosylation (GO:0006486) |
Pathways
• O-mannosyl glycan biosynthesis (Reactome: R-HSA-5173105)
• Dystroglycan-related diseases (Reactome: R-HSA-2467813)
Protein Summary
Beta-1,3-N-acetylgalactosaminyltransferase 2 (B3GALNT2) is a type II transmembrane protein localized to the Golgi apparatus. It catalyzes the transfer of GalNAc from UDP-GalNAc to O-mannose residues on alpha-dystroglycan, forming the GalNAc-beta1,3-GlcNAc linkage. This modification is critical for the functional maturation of dystroglycan, enabling its interaction with laminin, neurexin, and other extracellular matrix components. Defects in this enzyme lead to hypoglycosylation of alpha-dystroglycan, resulting in congenital muscular dystrophy with brain and eye anomalies.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| B3GALNT2 Knockout HEK293 Cell Line | EDJ-KQ10839 | Human | 148789 | Details Get a Quote |
| B3GALNT2 Knockout A-549 Cell Line | EDJ-KQ38495 | Human | 148789 | Details Get a Quote |
| B3GALNT2 Knockout HCT 116 Cell Line | EDJ-KQ38496 | Human | 148789 | Details Get a Quote |
| B3GALNT2 Knockout HeLa Cell Line | EDJ-KQ38497 | Human | 148789 | Details Get a Quote |
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