NM_001103.4:c.776C>T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BS2

The NM_001103.4(ACTN2):c.776C>T(p.Ala259Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000155 in 1,614,120 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A259T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000016 ( 0 hom. )

Consequence

ACTN2
NM_001103.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 7.91

Publications

4 publications found

Variant links:

Genes affected

ACTN2 (HGNC:164): (actinin alpha 2) Alpha actinins belong to the spectrin gene superfamily which represents a diverse group of cytoskeletal proteins, including the alpha and beta spectrins and dystrophins. Alpha actinin is an actin-binding protein with multiple roles in different cell types. In nonmuscle cells, the cytoskeletal isoform is found along microfilament bundles and adherens-type junctions, where it is involved in binding actin to the membrane. In contrast, skeletal, cardiac, and smooth muscle isoforms are localized to the Z-disc and analogous dense bodies, where they help anchor the myofibrillar actin filaments. This gene encodes a muscle-specific, alpha actinin isoform that is expressed in both skeletal and cardiac muscles. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2013]

ACTN2 Gene-Disease associations (from GenCC):

intrinsic cardiomyopathy
Inheritance: AD Classification: DEFINITIVE, MODERATE Submitted by: Laboratory for Molecular Medicine, ClinGen
myopathy, congenital, with structured cores and z-line abnormalities
Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
dilated cardiomyopathy 1AA
Inheritance: AD Classification: MODERATE, LIMITED Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Ambry Genetics
familial isolated dilated cardiomyopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
heart conduction disease
Inheritance: AD Classification: LIMITED Submitted by: Genomics England PanelApp
myopathy, distal, 6, adult-onset, autosomal dominant
Inheritance: AD, Unknown Classification: LIMITED Submitted by: Broad Center for Mendelian Genomics, Labcorp Genetics (formerly Invitae)

ACTN2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

BS2

High AC in GnomAdExome4 at 24 AD,Unknown gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTN2	NM_001103.4 link	c.776C>T	p.Ala259Val	missense_variant	Exon 8 of 21	ENST00000366578.6	NP_001094.1	P35609-1
ACTN2	NR_184402.1 link	n.1037C>T		non_coding_transcript_exon_variant	Exon 9 of 23
ACTN2	NM_001278343.2 link	c.783+1195C>T		intron_variant	Intron 8 of 20		NP_001265272.1	P35609-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACTN2	ENST00000366578.6 link	c.776C>T	p.Ala259Val	missense_variant	Exon 8 of 21	1	NM_001103.4	ENSP00000355537.4		P35609-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152192

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000796

AC:

AN:

251404

AF XY:

0.0000147

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS 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:

0.0000164

AC:

AN:

1461810

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

727204

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53414

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000189

AC:

AN:

1111944

Other (OTH)

AF:

0.00

AC:

AN:

60390

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.469

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152310

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74478

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41566

American (AMR)

AF:

0.00

AC:

AN:

15300

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10606

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68040

Other (OTH)

AF:

0.00

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000312

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Primary familial hypertrophic cardiomyopathy;C2677338:Dilated cardiomyopathy 1AA

Uncertain:1

Jan 16, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 259 of the ACTN2 protein (p.Ala259Val). This variant is present in population databases (rs566552494, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with ACTN2-related conditions. ClinVar contains an entry for this variant (Variation ID: 463217). 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 ACTN2 protein function with a negative predictive value of 80%. 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. -

Dilated cardiomyopathy 1AA;C5203349:Myopathy, distal, 6, adult-onset, autosomal dominant;C5231445:Myopathy, congenital, with structured cores and z-line abnormalities

Uncertain:1

Oct 01, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Uncertain:1

Jun 28, 2021

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Has not been previously published as pathogenic or benign to our knowledge; Reported in ClinVar as a variant of uncertain significance (ClinVar Variant ID# 463217; Landrum et al., 2016); Not observed at significant frequency in large population cohorts (Lek et al., 2016); 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: 26582918, 27535533) -

Cardiovascular phenotype

Uncertain:1

Aug 17, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.A259V variant (also known as c.776C>T), located in coding exon 8 of the ACTN2 gene, results from a C to T substitution at nucleotide position 776. The alanine at codon 259 is replaced by valine, an amino acid with similar properties. This alteration has been reported in association with cardiomyopathy (Ware SM et al. Am J Hum Genet, 2022 Feb;109:282-298; Akinrinade O et al. J Cardiovasc Transl Res, 2023 Jul;:). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.56

BayesDel_addAF

Uncertain

0.12

BayesDel_noAF

Uncertain

0.030

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.66

.;D

Eigen

Pathogenic

0.70

Eigen_PC

Pathogenic

0.74

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.75

T;D

M_CAP

Uncertain

0.19

MetaRNN

Uncertain

0.69

D;D

MetaSVM

Uncertain

0.14

MutationAssessor

Benign

1.2

.;L

PhyloP100

7.9

PrimateAI

Pathogenic

0.82

PROVEAN

Uncertain

-3.1

.;D

REVEL

Uncertain

0.59

Sift

Uncertain

0.0050

.;D

Sift4G

Uncertain

0.0070

D;T

Polyphen

1.0

.;D

Vest4

0.67

MutPred

0.40

.;Loss of disorder (P = 0.0918);

MVP

0.82

MPC

2.0

ClinPred

0.99

GERP RS

5.4

Varity_R

0.58

gMVP

0.63

Mutation Taster

=7/93

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over