Is EXT2 p.Leu549= (c.1645C>T) pathogenic?

EXT2 p.Leu549= (c.1645C>T) is classified Conflicting classifications of pathogenicity in EXT2 (ClinVar, Conflicting submitters, 5 submitters; last evaluated 2026-01-16). Ultra-rare (popmax 0.0822%, mid); Associated with exostoses, multiple, type 2.

What condition is associated with EXT2 p.Leu549= (c.1645C>T)?

EXT2 p.Leu549= (c.1645C>T) is associated with exostoses, multiple, type 2 (ClinVar).

How common is EXT2 p.Leu549= (c.1645C>T) in the general population?

EXT2 p.Leu549= (c.1645C>T) is ultra-rare (popmax 0.0822%, mid) (gnomAD).

How is Multiple osteochondromas inherited?

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

EXT2 p.Leu549=

c.1645C>T · rs142565472 · VCV290768

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 5 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0822%, mid)

Conditions

exostoses, multiple, type 2

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 4	GERP 1.8, phastCons 1
Overall
CADD	12.16	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0822% Middle Eastern · 5/6,082 alleles

Filtering AF 0.0596% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0581%

Overall 0.049% 791/1,613,936 alleles · ultra-rare exomes 751/1,461,796 · genomes 40/152,140 · joint denominator

Ancestry group	Frequency	1 in
Middle Easterngrpmax	0.0822%	1,216
European (non-Finnish)	0.0635%	1,575
Remaining individualsnot grpmax-eligible	0.04%	2,499
African / African-American	0.0134%	7,490
Admixed American	0.00333%	30,000

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: EXT2
Protein: p.Leu549=
Coding: c.1645C>T
MANE Select: NM_207122
dbSNP: rs142565472
Type: single nucleotide variant
Location: chr11:44206942 (GRCh38)
Gene constraint: LOEUF 0.775 · pLI <0.01 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 87.59 · 6 PDB
Residue 549: 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.Leu549Pro Uncertain significance ★ ⚠ 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-leu549 (accessed [today's date]).

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