EXT1
Chr 8ADSomaticexostosin glycosyltransferase 1
Also known as: EXT, LGCR, LGS, TRPS2, TTV
This gene encodes an endoplasmic reticulum glycosyltransferase that catalyzes heparan sulfate chain elongation during biosynthesis. Loss-of-function mutations cause multiple exostoses type 1, an autosomal dominant disorder characterized by benign bone tumors that can undergo malignant transformation to chondrosarcoma. The pathogenic mechanism involves haploinsufficiency leading to disrupted heparan sulfate production and abnormal bone growth regulation.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly LoF-intolerant (top ~10% of genes)
Mild missense constraint
The highest-scoring mechanism for this gene is loss-of-function (haploinsufficiency).
Literature Evidence
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312. Mechanism ranking also informed by gnomAD constraint, ClinVar, and ClinGen data.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
EXT1 · 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
Descriptive Analysis of Surgeries in Patients With Multiple Osteochondromas
RECRUITINGRegistry of Multiple Osteochondromas
RECRUITINGExternal Resources
Links to major genomics databases and tools