Is ACTA2 p.Cys19Arg (c.55T>C) pathogenic?

ACTA2 p.Cys19Arg (c.55T>C) is classified Likely pathogenic in ACTA2 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2024-03-11). AlphaMissense: likely pathogenic (0.9982); Absent from gnomAD v4.1; Associated with aortic aneurysm, familial thoracic 6.

What condition is associated with ACTA2 p.Cys19Arg (c.55T>C)?

ACTA2 p.Cys19Arg (c.55T>C) is associated with aortic aneurysm, familial thoracic 6 (ClinVar).

How common is ACTA2 p.Cys19Arg (c.55T>C) in the general population?

ACTA2 p.Cys19Arg (c.55T>C) is absent from gnomAD v4.1 (gnomAD).

What do computational predictors say about ACTA2 p.Cys19Arg (c.55T>C)?

AlphaMissense predicts likely pathogenic (score 0.9982) — an in-silico prediction, not a clinical call.

ACTA2 p.Cys19Arg

Q: How is Multisystemic smooth muscle dysfunction syndrome inherited?

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

c.55T>C · rs2133273980 · VCV1054067

Likely pathogenic Multiple submitters

Classification

Likely pathogenic

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

AlphaMissense

likely pathogenic

0.9982 · ACMG-weighted

gnomAD v4.1

Absent

absent from gnomAD v4.1

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

aortic aneurysm, familial thoracic 6

Computational evidence

Protein change
AlphaMissense	0.9982	likely pathogenic ✓ concordant with ClinVar
REVEL	0.764	pathogenic-leaning
SaProt	LLR -14.52	damaging
⇒ AlphaMissense, REVEL and SaProt all call this damaging.
Splicing
SpliceAI	<0.2	all four deltas below 0.2 · A>C here scores Δ0.34 · evaluated, not missing
Constraint at this position
Conservation	phyloP 8	GERP 0.74, phastCons 1
Regional constraint	o/e 0.47	unconstrained · MANE · 14 kb · p 5.8e-32 · regional, not allelic
Overall
CADD	27.7	PHRED · no single calibrated threshold — expert panels disagree

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

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: ACTA2
Protein: p.Cys19Arg
Coding: c.55T>C
MANE Select: NM_001613
dbSNP: rs2133273980
Type: single nucleotide variant
Location: chr10:88948876 (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

For Multisystemic smooth muscle dysfunction syndrome (Orphanet):

Inheritance: Unknown
Onset: Infancy

Similar variants

ACTA2 p.Cys19Ser 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
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-cys19arg (accessed [today's date]).

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