EXTL1
Chr 1exostosin like glycosyltransferase 1
Also known as: EXTL
EXTL1 encodes a glycosyltransferase that transfers N-acetylglucosamine during heparan sulfate biosynthesis, which is essential for proper cell signaling and development. Mutations cause skeletal dysplasia with multiple osteochondromas, developmental delay, and intellectual disability through autosomal recessive inheritance. The gene shows extremely high constraint against loss-of-function variants, indicating its critical importance for normal development.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
ClinVar Variant Classifications
133 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 | 0 | 5 | 0 | 5 |
Likely Pathogenic | 0 | 0 | 0 | 0 | 0 |
VUS | 0 | 103 | 4 | 0 | 107 |
Likely Benign | 0 | 12 | 0 | 0 | 12 |
Benign | 0 | 0 | 0 | 0 | 0 |
| Total | 0 | 115 | 9 | 0 | 124 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
EXTL1 · 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
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools