What condition is associated with ACTC1 p.Arg256Cys (c.766C>T)?

ACTC1 p.Arg256Cys (c.766C>T) is associated with hypertrophic cardiomyopathy 11, atrial septal defect 5, dilated cardiomyopathy 1R (ClinVar).

How common is ACTC1 p.Arg256Cys (c.766C>T) in the general population?

ACTC1 p.Arg256Cys (c.766C>T) is no allele count reported in gnomAD v4.1 (AN 1,614,202) (gnomAD).

What do computational predictors say about ACTC1 p.Arg256Cys (c.766C>T)?

AlphaMissense predicts likely pathogenic (score 0.9677) — an in-silico prediction, not a clinical call.

ACTC1 p.Arg256Cys

Q: Is ACTC1 p.Arg256Cys (c.766C>T) pathogenic?

ACTC1 p.Arg256Cys (c.766C>T) is classified Likely pathogenic in ACTC1 (ClinVar, Single submitter, 1 submitter). AlphaMissense: likely pathogenic (0.9677); No allele count reported in gnomAD v4.1 (AN 1,614,202); Associated with hypertrophic cardiomyopathy 11.

c.766C>T · VCV3382680

Likely pathogenic Single submitter

Classification

Likely pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely pathogenic

0.9677 · ACMG-weighted

gnomAD v4.1

Not reported

no allele count reported in gnomAD v4.1 (AN 1,614,202)

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

hypertrophic cardiomyopathy 11

Computational evidence

Protein change
AlphaMissense	0.9677	likely pathogenic ✓ concordant with ClinVar
REVEL	0.958	strongly pathogenic-leaning
SaProt	LLR -11.14	damaging
⇒ AlphaMissense, REVEL and SaProt all call this damaging.
Splicing
SpliceAI	—	not looked up on this page · why
Constraint at this position
Conservation	phyloP 12	GERP 2.3, phastCons 1
Regional constraint	o/e 0.16	constrained · MANE · 2,113 bp · p 8.3e-37 · regional, not allelic
Overall
CADD	33.0	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

No allele count reported in gnomAD v4.1 (AN 1,614,202). This is missing data, not an absence: the variant may or may not be present in gnomAD. Rarity (ACMG PM2) and BA1/BS1 cannot be assessed for it.

Variant & gene context

Gene: ACTC1
Protein: p.Arg256Cys
Coding: c.766C>T
Type: single nucleotide variant
Location: chr15:34792132 (GRCh38)

Full ACTC1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

hypertrophic cardiomyopathy 11 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: atrial septal defect 5 dilated cardiomyopathy 1R

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/actc1-p-arg256cys (accessed [today's date]).

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