B4GALT7: Beta-1,4-Galactosyltransferase 7
A key enzyme in proteoglycan biosynthesis, associated with Ehlers-Danlos syndrome and other connective tissue disorders.
Gene Information Card
| Symbol | B4GALT7 |
|---|---|
| Full Name | Beta-1,4-galactosyltransferase 7 |
| Gene Type | Protein coding |
| Chromosomal Location | 5q35.3 |
| NCBI Gene ID | 11285 ncbi.nlm.nih.gov/gene/11285 |
| Ensembl ID | ENSG00000113578 |
| UniProt ID | Q9UBV7 |
| OMIM ID | 604327 |
| HGNC ID | 930 |
| Aliases | XGALT2, GALT7, beta4Gal-T7, GalT7 |
Description
B4GALT7 encodes beta-1,4-galactosyltransferase 7, a Golgi enzyme that transfers galactose to xylose residues in the linker region of proteoglycans. This step is essential for the biosynthesis of glycosaminoglycan chains (e.g., heparan sulfate, chondroitin sulfate). Mutations in B4GALT7 cause a form of Ehlers-Danlos syndrome (spondylodysplastic type) and are linked to altered extracellular matrix integrity.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Ehlers-Danlos syndrome, spondylodysplastic type 1 (EDSSPD1) | Loss-of-function mutations impair proteoglycan linker synthesis, leading to defective extracellular matrix and connective tissue fragility. | OMIM #130070; multiple case reports |
| Geroderma osteodysplasticum (GO) | Biallelic B4GALT7 mutations disrupt glycosaminoglycan assembly, causing skeletal abnormalities and skin laxity. | OMIM #231070; rare variant studies |
| Short stature, developmental delay, and skeletal anomalies | Reduced enzyme activity affects growth plate proteoglycans, impairing endochondral ossification. | ClinVar; case series |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Adipose tissue | 12.5 | Medium |
| Brain | 8.3 | Low |
| Colon | 15.1 | Medium |
| Heart | 10.2 | Medium |
| Kidney | 14.8 | Medium |
| Liver | 9.6 | Low |
| Lung | 11.3 | Medium |
| Muscle | 7.4 | Low |
| Skin | 18.9 | Medium |
| Testis | 6.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 22.4 | Cervical carcinoma; high expression |
| HEK 293 | 18.7 | Embryonic kidney; moderate expression |
| HepG2 | 14.2 | Hepatocellular carcinoma; moderate expression |
| K562 | 9.8 | Leukemia; low expression |
| MCF7 | 11.5 | Breast cancer; moderate expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.808C>T (p.Arg270Cys) | Missense | Rare (MAF <0.01%) | Reduced enzyme activity; associated with EDSSPD1 |
| c.641G>A (p.Arg214His) | Missense | Rare | Impaired galactosyltransferase function; linked to GO |
| c.1A>G (p.Met1Val) | Start loss | Very rare | Complete loss of protein; severe phenotype |
| c.907G>A (p.Gly303Arg) | Missense | Rare | Decreased stability and activity; reported in ClinVar |
Mutation functional classification
Loss of Function (LOF)
Most B4GALT7 mutations (missense, start loss) reduce or abolish galactosyltransferase activity, leading to incomplete proteoglycan linker synthesis.
Gain of Function (GOF)
No evidence of gain-of-function mutations in B4GALT7.
Dominant Negative (DN)
Not reported; disease inheritance is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • galactosyltransferase activity (GO:0008378) | • Golgi apparatus (GO:0005794) |
| • integral component of membrane (GO:0016021) | • protein glycosylation (GO:0006486) |
| • glycosaminoglycan metabolic process (GO:0030203) | • heparan sulfate proteoglycan biosynthetic process (GO:0015014) |
Pathways
• Proteoglycan biosynthesis (Reactome: R-HSA-1971475)
• Glycosaminoglycan metabolism (KEGG: hsa00532)
• Extracellular matrix organization (Reactome: R-HSA-1474244)
Protein Summary
Beta-1,4-galactosyltransferase 7 is a 327-amino acid type II transmembrane protein localized to the Golgi apparatus. It catalyzes the transfer of galactose from UDP-galactose to xylose residues on the tetrasaccharide linker of proteoglycans. This step is critical for the elongation of glycosaminoglycan chains. The protein has a short N-terminal cytoplasmic tail, a transmembrane domain, and a large C-terminal catalytic domain. Mutations that reduce its activity lead to connective tissue disorders due to defective proteoglycan synthesis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| B4GALT7 Knockout HEK293 Cell Line | EDJ-KQ3867 | Human | 11285 | Details Get a Quote |
| B4GALT7 Knockout A-549 Cell Line | EDJ-KQ26065 | Human | 11285 | Details Get a Quote |
| B4GALT7 Knockout HCT 116 Cell Line | EDJ-KQ26066 | Human | 11285 | Details Get a Quote |
| B4GALT7 Knockout HeLa Cell Line | EDJ-KQ24712 | Human | 11285 | Details Get a Quote |
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