rs727504399

Variant names:

• chr15-34794733-C-T
• rs727504399
• NM_005159.5:c.76G>A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3 PP5

The NM_005159.5(ACTC1):​c.76G>A​(p.Asp26Asn) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,138 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ACTC1 NM_005159.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 6.12

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]

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

ACMG classification

Verdict is Uncertain_significance. Variant got 5 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, 0.812
• PP5: Variant 15-34794733-C-T is Pathogenic according to our data. Variant chr15-34794733-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 177917.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Pathogenic=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTC1	NM_005159.5	c.76G>A	p.Asp26Asn	missense_variant	Exon 2 of 7	ENST00000290378.6	NP_005150.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACTC1	ENST00000290378.6	c.76G>A	p.Asp26Asn	missense_variant	Exon 2 of 7	1	NM_005159.5	ENSP00000290378.4
ACTC1	ENST00000560563.2	n.182G>A		non_coding_transcript_exon_variant	Exon 2 of 6	2
GJD2-DT	ENST00000503496.6	n.300-15763C>T		intron_variant	Intron 2 of 2	2
GJD2-DT	ENST00000671663.1	n.95-15763C>T		intron_variant	Intron 1 of 1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461138 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726892

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

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

Oct 21, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces aspartic acid, which is acidic and polar, with asparagine, which is neutral and polar, at codon 26 of the ACTC1 protein (p.Asp26Asn). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with ACTC1-related conditions and hypertrophic cardiomyopathy (PMID: 27532257, 30600190). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 177917). 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%. For these reasons, this variant has been classified as Pathogenic. -

Hypertrophic cardiomyopathy 11 Pathogenic:1

Aug 02, 2024

Servicio Canario de Salud, Hospital Universitario Nuestra Sra. de Candelaria

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.76G>A (p.Asp26Asn) ACTC1 variant has been reported in our laboratory in a 67-year-old patient with diagnosis of hypertrophic cardiomyopathy. Father (sudden death 30y) and paternal grandmother (sudden death 50y). In our Hospital, it has been reported in another family with hypertrophic cardiomyopathy with positive segregation. This variant is present in population databases (gnomAD allele frequency 0.0000006198). This variant has been previously reported in a patients with hypertrophic cardiomyopathy [PMID 27532257, 30600190]. ClinVar contains an entry for this variant (Variation ID: 117917). In silico analysis (CADD, Revel) supports that this missense variant has a deleterious effect on protein structure/function. In summary, c.76G>A (p.Asp26Asn) ACTC1 variant meets our criteria to be classified as pathogenic based upon its absence from controls, computational evidence of pathogenicity in this family and having been widely described in relation to the patient´s phenotype. -

not specified Uncertain:1

Feb 11, 2013

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

proposed classification - variant undergoing re-assessment, contact laboratory -

not provided Uncertain:1

Jul 11, 2018

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Asp26Asn (GAT>AAT):c.76 G>A in exon 2 of the ACTC1 gene (NM_005159.4). The Asp26Asn variant in the ACTC1 gene has not been reported as a disease-causing mutation or as a benign polymorphism to our knowledge. Asp26Asn results in a semi-conservative amino acid substitution of a negatively charged Aspartic acid residue with a neutral, polar Asparagine residue at a position that is conserved across species. In silico analysis predicts Asp26Asn is probably damaging to the protein structure/function. Furthermore, the NHLBI ESP Exome Variant Server reports Asp26Asn was not observed in approximately 6,500 samples from individuals of European and African American backgrounds, indicating it is not a common benign variant in these populations. Nevertheless, no mutations in surrounding residues of the ACTC1 gene have been reported in association with HCM, suggesting this region of the protein may be tolerant of change. With the clinical and molecular information available at this time, we cannot definitively determine if Asp26Asn is a disease-causing mutation or a rare benign variant. The variant is found in HCM panel(s). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
CardioboostCm	Uncertain	0.46
BayesDel_addAF	Uncertain	0.087	D
BayesDel_noAF	Benign	-0.11
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.93	D
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.62	D
MetaRNN	Pathogenic	0.81	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.2	M
PrimateAI	Pathogenic	0.88	D
PROVEAN	Benign	-2.1	N
REVEL	Pathogenic	0.74
Sift4G	Uncertain	0.023	D
Polyphen		0.95	P
Vest4		0.43
MutPred		0.62		Loss of disorder (P = 0.1505);
MVP		0.92
MPC		1.7
ClinPred		0.98	D
GERP RS		4.2
Varity_R		0.84
gMVP		0.93

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

Other links and lift over

dbSNP: rs727504399; hg19: chr15-35086934; COSMIC: COSV51757846; COSMIC: COSV51757846;