Is EXT2 p.Gln336Ter (c.1006C>T) pathogenic?

EXT2 p.Gln336Ter (c.1006C>T) is classified Pathogenic in EXT2 (ClinVar, Multiple submitters, 3 submitters; last evaluated 2023-12-27). Absent from gnomAD v4.1; Associated with exostoses, multiple, type 2.

What condition is associated with EXT2 p.Gln336Ter (c.1006C>T)?

EXT2 p.Gln336Ter (c.1006C>T) is associated with exostoses, multiple, type 2 (ClinVar).

How common is EXT2 p.Gln336Ter (c.1006C>T) in the general population?

EXT2 p.Gln336Ter (c.1006C>T) is absent from gnomAD v4.1 (gnomAD).

How is Multiple osteochondromas inherited?

Typically Autosomal dominant (Orphanet). A genetic counselor can assess individual risk for a family.

EXT2 p.Gln336Ter

c.1006C>T · rs1954414269 · VCV935468

Pathogenic Multiple submitters

Classification

Pathogenic

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Absent

absent from gnomAD v4.1

Conditions

exostoses, multiple, type 2

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Consequence	nonsense (stop-gain)	predicted loss-of-function in a haploinsufficient gene (ClinGen)
NMD	predicted	premature termination codon in exon 6 of 14
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP 2.6	GERP 1.7, phastCons 0.99
Overall
CADD	38.0	PHRED · no single calibrated threshold — expert panels disagree

Predicted loss-of-function is descriptive, not an applied PVS1 code.

Population frequency

gnomAD v4.1 · exomes + genomes

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: EXT2
Protein: p.Gln336Ter
Coding: c.1006C>T
MANE Select: NM_207122
dbSNP: rs1954414269
Type: single nucleotide variant
Location: chr11:44126882 (GRCh38)
Gene constraint: LOEUF 0.775 · pLI <0.01 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 87.59 · 6 PDB
Residue 336: an α-helix

Full EXT2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

exostoses, multiple, type 2 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Multiple osteochondromas (Orphanet):

Inheritance: Autosomal dominant
Onset: Childhood
Prevalence: >1 / 1000 (Specific population)

Similar variants

EXT2 p.Gln336= Likely benign ★ same residue
EXT2 c.1079+1G>A Pathogenic ★★ same condition
EXT2 c.1079+1G>T Pathogenic ★★ same condition
EXT2 c.1173+1G>A Pathogenic ★★ same condition
EXT2 c.1662+1G>C Likely pathogenic ★★ same condition
EXT2 c.536+1G>A Pathogenic ★★ same condition
EXT2 c.626+1G>A Pathogenic ★★ same condition
EXT2 c.626+1G>C 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/ext2-p-gln336ter (accessed [today's date]).

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