Is EXT1 p.Lys110Arg (c.329A>G) pathogenic?

EXT1 p.Lys110Arg (c.329A>G) is classified Uncertain significance in EXT1 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2025-08-19). AlphaMissense: likely benign (0.0592); Very rare (popmax 0.00891%, eas); Associated with chondrosarcoma.

What condition is associated with EXT1 p.Lys110Arg (c.329A>G)?

EXT1 p.Lys110Arg (c.329A>G) is associated with chondrosarcoma, hereditary multiple osteochondromas (ClinVar).

How common is EXT1 p.Lys110Arg (c.329A>G) in the general population?

EXT1 p.Lys110Arg (c.329A>G) is very rare (popmax 0.00891%, eas) (gnomAD).

How is Chondrosarcoma inherited?

Typically Not applicable, Unknown (Orphanet). A genetic counselor can assess individual risk for a family.

What do computational predictors say about EXT1 p.Lys110Arg (c.329A>G)?

AlphaMissense predicts likely benign (score 0.0592) — an in-silico prediction, not a clinical call.

EXT1 p.Lys110Arg

c.329A>G · rs1178109514 · VCV1427094

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

AlphaMissense

likely benign

0.0592 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00891%, eas)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

chondrosarcoma

Computational evidence

Protein change
AlphaMissense	0.0592	likely benign
REVEL	0.267	benign-leaning
SaProt	LLR -5.22	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 6.1	GERP 5.8, phastCons 1
Regional constraint	o/e 1.10	unconstrained · MANE · 371 bp · p 0.2 · regional, not allelic
Overall
CADD	22.5	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean tolerated — a triage signal, not a reclassification

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00891% East Asian · 4/44,882 alleles

Filtering AF 0.00298% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0018%

Overall 0.000248% 4/1,614,178 alleles · very rare exomes 4/1,461,894 · genomes 0/152,284 · joint denominator

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: EXT1
Protein: p.Lys110Arg
Coding: c.329A>G
MANE Select: NM_000127
dbSNP: rs1178109514
Type: single nucleotide variant
Location: chr8:118110718 (GRCh38)
Gene constraint: LOEUF 0.339 · pLI 1.00 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 84.67 · 6 PDB
Residue 110: a turn

Full EXT1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

chondrosarcoma — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: hereditary multiple osteochondromas

For Chondrosarcoma (Orphanet):

Inheritance: Not applicable, Unknown
Onset: Adult
Prevalence: 1-9 / 1 000 000 (Europe)

Similar variants

EXT1 c.1056+1G>A Pathogenic ★★ same condition
EXT1 c.1056+1G>T Pathogenic ★★ same condition
EXT1 c.1165-1G>A Pathogenic ★★ same condition
EXT1 c.1285-1G>C Pathogenic ★★ same condition
EXT1 c.1417+1G>A Pathogenic ★★ same condition
EXT1 c.1417+1G>T Pathogenic ★★ same condition
EXT1 c.1418-1G>A Pathogenic ★★ same condition
EXT1 c.1418-2A>G Pathogenic ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/ext1-p-lys110arg (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown