1-236742980-C-G

Variant names:

• chr1-236742980-C-G
• rs148189507
• NM_001103.4:c.1192C>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_001103.4(ACTN2):​c.1192C>G​(p.Arg398Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 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. R398C) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ACTN2 NM_001103.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.14
• Publications: 8 publications found

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)

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.858

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTN2	NM_001103.4	c.1192C>G	p.Arg398Gly	missense_variant	Exon 11 of 21	ENST00000366578.6	NP_001094.1
ACTN2	NM_001278343.2	c.1192C>G	p.Arg398Gly	missense_variant	Exon 11 of 21		NP_001265272.1
ACTN2	NR_184402.1	n.1564C>G		non_coding_transcript_exon_variant	Exon 13 of 23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACTN2	ENST00000366578.6	c.1192C>G	p.Arg398Gly	missense_variant	Exon 11 of 21	1	NM_001103.4	ENSP00000355537.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Primary familial hypertrophic cardiomyopathy;C2677338:Dilated cardiomyopathy 1AA Uncertain:1

Mar 18, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 398 of the ACTN2 protein (p.Arg398Gly). This variant is not present in population databases (gnomAD no frequency). 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: 463189). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt ACTN2 protein function. -

Cardiovascular phenotype Uncertain:1

Nov 17, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R398G variant (also known as c.1192C>G), located in coding exon 11 of the ACTN2 gene, results from a C to G substitution at nucleotide position 1192. The arginine at codon 398 is replaced by glycine, an amino acid with dissimilar properties. This alteration has been reported in a Brugada syndrome cohort and in a cardiomyopathy/arrhythmia genetic testing cohort; however, clinical details were limited, and additional cardiac variants were detected in some cases (Zhang L et al. Mayo Clin Proc, 2016 Nov;91:1503-1514; van Lint FHM et al. Neth Heart J, 2019 Jun;27:304-309). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. 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	0.96
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.75	.;.;D
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Benign	0.083	D
MetaRNN	Pathogenic	0.86	D;D;D
MetaSVM	Uncertain	-0.17	T
MutationAssessor	Pathogenic	3.4	.;M;M
PhyloP100		3.1
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-6.2	.;D;D
REVEL	Uncertain	0.44
Sift	Uncertain	0.0010	.;D;D
Sift4G	Uncertain	0.0020	D;D;D
Polyphen		0.98	.;.;D
Vest4		0.89
MutPred		0.50		.;Loss of MoRF binding (P = 0.0112);Loss of MoRF binding (P = 0.0112);
MVP		0.86
MPC		0.94
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.89
gMVP		0.68
Mutation Taster		=22/78	disease causing

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

Other links and lift over

dbSNP: rs148189507; hg19: chr1-236906280;