Is ACTA2 p.Thr326= (c.978C>T) pathogenic?

ACTA2 p.Thr326= (c.978C>T) is classified Likely benign in ACTA2 (ClinVar, Multiple submitters, 3 submitters; last evaluated 2024-03-28). Very rare (popmax 0.00449%, nfe); Associated with familial thoracic aortic aneurysm and aortic dissection.

How common is ACTA2 p.Thr326= (c.978C>T) in the general population?

ACTA2 p.Thr326= (c.978C>T) is very rare (popmax 0.00449%, nfe) (gnomAD).

ACTA2 p.Thr326=

Q: What condition is associated with ACTA2 p.Thr326= (c.978C>T)?

ACTA2 p.Thr326= (c.978C>T) is associated with familial thoracic aortic aneurysm and aortic dissection, aortic aneurysm, familial thoracic 6 (ClinVar).

Q: How is Familial thoracic aortic aneurysm and aortic dissection inherited?

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

c.978C>T · rs766393962 · VCV2200317

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00449%, nfe)

Conditions

familial thoracic aortic aneurysm and aortic dissection

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 4.5	GERP 0.096, phastCons 1
Overall
CADD	11.93	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00449% European (non-Finnish) · 53/1,179,912 alleles

Filtering AF 0.0035% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00318%

Overall 0.00335% 54/1,613,812 alleles · very rare exomes 53/1,461,672 · genomes 1/152,140 · joint denominator

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.00449%	22,262
African / African-American	0.00133%	74,910

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: ACTA2
Protein: p.Thr326=
Coding: c.978C>T
MANE Select: NM_001613
dbSNP: rs766393962
Type: single nucleotide variant
Location: chr10:88938073 (GRCh38)
Gene constraint: LOEUF 0.472 · pLI 0.99 · ClinGen HI 1/3 (gnomAD)
Structure: AlphaFold pLDDT 95.43
Residue 326: a UniProt-annotated variant site (in aat6)

Full ACTA2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

familial thoracic aortic aneurysm and aortic dissection — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: aortic aneurysm, familial thoracic 6

For Familial thoracic aortic aneurysm and aortic dissection (Orphanet):

Inheritance: Autosomal dominant
Onset: Adolescent, Adult, Childhood

Similar variants

ACTA2 p.Thr326Asn Uncertain significance ★★ ⚠ same residue
ACTA2 p.Thr326Ala Uncertain significance ★ same residue
ACTA2 p.Arg118Gln Pathogenic/Likely pathogenic ★★ same condition
ACTA2 p.Arg149Cys Pathogenic ★★ same condition
ACTA2 p.Arg149Leu Pathogenic/Likely pathogenic ★★ same condition
ACTA2 p.Arg179Cys Pathogenic ★★ same condition
ACTA2 p.Arg179His Pathogenic ★★ same condition
ACTA2 p.Arg198Cys Pathogenic/Likely 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/acta2-p-thr326 (accessed [today's date]).

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