Is ACTA2 p.Arg314Ter (c.940C>T) pathogenic?

ACTA2 p.Arg314Ter (c.940C>T) is classified Pathogenic/Likely pathogenic in ACTA2 (ClinVar, Multiple submitters, 6 submitters; last evaluated 2026-02-26). Very rare (popmax 6.84e-05%); Associated with aortic aneurysm, familial thoracic 6.

What condition is associated with ACTA2 p.Arg314Ter (c.940C>T)?

ACTA2 p.Arg314Ter (c.940C>T) is associated with aortic aneurysm, familial thoracic 6, familial thoracic aortic aneurysm and aortic dissection (ClinVar).

How common is ACTA2 p.Arg314Ter (c.940C>T) in the general population?

ACTA2 p.Arg314Ter (c.940C>T) is very rare (popmax 6.84e-05%) (gnomAD).

ACTA2 p.Arg314Ter

Q: How is Multisystemic smooth muscle dysfunction syndrome inherited?

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

c.940C>T · rs886038978 · VCV263926

Pathogenic/Likely pathogenic Multiple submitters

Classification

Pathogenic/Likely pathogenic

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 6 submitters

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Rare

very rare (popmax 6.84e-05%)

Conditions

aortic aneurysm, familial thoracic 6

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 LoF-intolerant gene
NMD	escapes	premature termination codon within the last 50 nt of the penultimate exon (8 of 9, 50 nt from its 3' end) — the truncated protein is likely expressed. PVS1 input, not an applied code
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 3.3	GERP -0.82, phastCons 1
Overall
CADD	37.0	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

Grpmax group 6.84e-05%

Overall 6.84e-05% 1/1,461,754 alleles · very rare

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.Arg314Ter
Coding: c.940C>T
MANE Select: NM_001613
dbSNP: rs886038978
Type: single nucleotide variant
Location: chr10:88938111 (GRCh38)
Gene constraint: LOEUF 0.472 · pLI 0.99 · ClinGen HI 1/3 (gnomAD)
Structure: AlphaFold pLDDT 95.43

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

Disease context

aortic aneurysm, familial thoracic 6 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: familial thoracic aortic aneurysm and aortic dissection

For Multisystemic smooth muscle dysfunction syndrome (Orphanet):

Inheritance: Unknown
Onset: Infancy

Similar variants

ACTA2 p.Arg314Gln Conflicting classifications of pathogenicity ★ 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
ACTA2 p.Arg198His 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-arg314ter (accessed [today's date]).

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