rs121912676

Variant names:

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2PP2PP3_Strong

The NM_005159.5(ACTC1):c.268C>T(p.His90Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

ACTC1
NM_005159.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:6

Conservation

PhyloP100: 10.0

Variant links:

Genes affected

ACTC1 (HGNC:143): (actin alpha cardiac muscle 1) Actins are highly conserved proteins that are involved in various types of cell motility. Polymerization of globular actin (G-actin) leads to a structural filament (F-actin) in the form of a two-stranded helix. Each actin can bind to four others. The protein encoded by this gene belongs to the actin family which is comprised of three main groups of actin isoforms, alpha, beta, and gamma. The alpha actins are found in muscle tissues and are a major constituent of the contractile apparatus. Defects in this gene have been associated with idiopathic dilated cardiomyopathy (IDC) and familial hypertrophic cardiomyopathy (FHC). [provided by RefSeq, Jul 2008]

ACTC1 links:

GJD2-DT (HGNC:55560): (GJD2 divergent transcript)

GJD2-DT links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the ACTC1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 15 curated pathogenic missense variants (we use a threshold of 10). The gene has 5 curated benign missense variants. Gene score misZ: 4.5244 (above the threshold of 3.09). Trascript score misZ: 6.3156 (above the threshold of 3.09). GenCC associations: The gene is linked to dilated cardiomyopathy, hypertrophic cardiomyopathy, atrial septal defect 5, arrhythmogenic right ventricular cardiomyopathy, familial isolated dilated cardiomyopathy, dilated cardiomyopathy 1R, hypertrophic cardiomyopathy 11.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.988

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTC1	NM_005159.5 link	c.268C>T	p.His90Tyr	missense_variant	Exon 3 of 7	ENST00000290378.6	NP_005150.1	P68032B3KPP5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACTC1	ENST00000290378.6 link	c.268C>T	p.His90Tyr	missense_variant	Exon 3 of 7	1	NM_005159.5	ENSP00000290378.4		P68032

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000795

AC:

AN:

251492

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135922

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461892

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727248

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

8.99e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:6

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Hypertrophic cardiomyopathy 11

Pathogenic:2

May 01, 2008

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Laboratorio de Analisis Clinicos, Hospital Valle de Los Pedroches

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ECG showed a sinus rhythm with a left bundle branch block. Echocardiography revealed asymmetric left ventricular hypertrophy with a maximum medium septal thickness of 16 mm. The left ventricular ejec- tion fraction was preserved, but the global longitudi- nal strain was reduced. There was no left ventricular outflow tract obstruction. The left atrium was dilated with increased filling pressure. The right ventricle was normofunctional, with an estimated systolic pulmonary pressure of 45 mm Hg. Cardiac magnetic resonance imaging confirmed the presence of left ventricular hypertrophy (Figure [B]). No areas of late gadolinium enhancement were observed. Genetic testing using a commercially available next-generation sequencing cardiomyopathy gene panel (https://www.healthin- code.com/) identified a heterozygous missense muta- tion in the ACTC1 gene (NM_005159.5:c.268C > T; NP_005150.1:p. His90Tyr). Eleven members tested positive. Four carriers and 2 noncarriers had been diagnosed with hypertension. All carriers over the age of 50 developed a partial or complete phenotype that was not observed in noncarriers or younger carriers. Four different intraventricular conduction disorder patterns were identified -

not specified

Uncertain:2

Sep 09, 2015

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.His90Tyr variant in ACTC1 has been reported in 3 individuals with HCM (Mor ita 2008, LMM unpublished data). This variant has also been identified in 1/6673 0 European chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.br oadinstitute.org; dbSNP rs121912676). Computational prediction tools and conserv ation analysis suggest that the p.His90Tyr variant may impact the protein, thoug h this information is not predictive enough to determine pathogenicity. In summa ry, the clinical significance of the p.His90Tyr variant is uncertain. -

Apr 05, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: ACTC1 c.268C>T (p.His90Tyr) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251492 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.268C>T has been reported in the literature in several individuals affected with Hypertrophic Cardiomyopathy (e.g. Morita_2008, Gomez_2017, Walsh_2017, Viswanathan_2017, Ho_2018). However, these reports do not provide unequivocal conclusions about association of the variant with Hypertrophic Cardiomyopathy. One publication reported experimental evidence evaluating an impact on protein function, and demonstrated that the variant resulted in an increased calcium sensitivity (Teng_2019). Three ClinVar submitters have assessed the variant since 2014, and all classified the variant as of uncertain significance. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Hypertrophic cardiomyopathy 11;C2748552:Atrial septal defect 5;C3150681:Dilated cardiomyopathy 1R

Uncertain:1

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces histidine, which is basic and polar, with tyrosine, which is neutral and polar, at codon 90 of the ACTC1 protein (p.His90Tyr). This variant is present in population databases (rs121912676, gnomAD 0.003%). This missense change has been observed in individual(s) with left ventricular hypertrophy or hypertrophic cardiomyopathy (PMID: 18403758, 27532257, 28356264, 29121657, 30297972, 36960733). ClinVar contains an entry for this variant (Variation ID: 18326). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt ACTC1 protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change affects ACTC1 function (PMID: 31481237). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

not provided

Uncertain:1

Feb 08, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Inconclusive functional studies indicate that while this variant, reported as H88Y using alternate nomenclature, leads to increased calcium sensitivity of contraction, it resulted in similar activity and motility compared to wild type (PMID: 28972856, 31481237); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 27532257, 28972856, 31481237, 28356264, 29121657, 18403758, 36960733, Valverde2021[CaseReport]) -

Hypertrophic cardiomyopathy

Uncertain:1

Dec 18, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces histidine with tyrosine at codon 90 of the ACTC1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). A functional study has shown that this variant causes increased calcium sensitivity in vitro (PMID: 31481237). This variant has been reported in six individuals affected with hypertrophic cardiomyopathy (PMID: 18403758, 27532257, 28356264, 29121657, ClinVar SCV000061992.5). This variant has been identified in 2/251492 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Cardiovascular phenotype

Uncertain:1

Oct 25, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.268C>T (p.H90Y) alteration is located in exon 3 (coding exon 2) of the ACTC1 gene. This alteration results from a C to T substitution at nucleotide position 268, causing the histidine (H) at amino acid position 90 to be replaced by a tyrosine (Y). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.95

CardioboostCm

Pathogenic

0.98

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.52

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.95

Eigen

Pathogenic

0.74

Eigen_PC

Pathogenic

0.79

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.97

M_CAP

Pathogenic

0.62

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

1.0

MutationAssessor

Uncertain

2.1

PrimateAI

Pathogenic

0.90

PROVEAN

Uncertain

-4.3

REVEL

Pathogenic

0.87

Sift4G

Benign

0.095

Polyphen

0.48

Vest4

0.95

MutPred

0.94

Gain of ubiquitination at K86 (P = 0.1079);

MVP

1.0

MPC

3.1

ClinPred

0.96

GERP RS

5.6

Varity_R

0.88

gMVP

0.98

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over