B4GALT1
Chr 9ARbeta-1,4-galactosyltransferase 1
Also known as: B4GAL-T1, CDG2D, CLDLFIB, GGTB2, GT1, GTB, beta4Gal-T1
The protein is a galactosyltransferase that transfers galactose residues to N-acetylglucosamine on glycoproteins and glycolipids in the Golgi apparatus, and also forms part of the lactose synthase complex in mammary tissue. Biallelic mutations cause congenital disorder of glycosylation type IId and a condition with combined low LDL and fibrinogen, inherited in an autosomal recessive pattern. The gene shows tolerance to loss-of-function variants (pLI 0.04, LOEUF 0.70), suggesting that complete loss of function may be compatible with survival but causes clinically significant glycosylation defects.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Mild missense constraint
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
100 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 0 | 1 | 4 | 0 | 5 |
Likely Pathogenic | 0 | 0 | 2 | 0 | 2 |
VUS | 1 | 52 | 6 | 0 | 59 |
Likely Benign | 0 | 3 | 10 | 8 | 21 |
Benign | 0 | 0 | 0 | 1 | 1 |
Conflicting | — | 1 | |||
| Total | 1 | 56 | 22 | 9 | 89 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
B4GALT1 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
External Resources
Links to major genomics databases and tools