1-236735637-A-G

Variant names:

• chr1-236735637-A-G
• rs794728963
• NM_001103.4:c.700A>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001103.4(ACTN2):​c.700A>G​(p.Ile234Val) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 1/1 splice prediction tools predict no significant impact on normal splicing. 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. I234L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: ACTN2 NM_001103.4 missense, splice_region
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.32
• Publications: 1 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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTN2	NM_001103.4	c.700A>G	p.Ile234Val	missense_variant, splice_region_variant	Exon 8 of 21	ENST00000366578.6	NP_001094.1
ACTN2	NR_184402.1	n.961A>G		splice_region_variant, non_coding_transcript_exon_variant	Exon 9 of 23
ACTN2	NM_001278343.2	c.783+1119A>G		intron_variant	Intron 8 of 20		NP_001265272.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACTN2	ENST00000366578.6	c.700A>G	p.Ile234Val	missense_variant, splice_region_variant	Exon 8 of 21	1	NM_001103.4	ENSP00000355537.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Jun 21, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals with a ACTN2-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25"). In summary, this variant has uncertain impact on ACTN2 function. The available evidence is currently insufficient to determine its role in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This sequence change replaces isoleucine with valine at codon 234 of the ACTN2 protein (p.Ile234Val). The isoleucine residue is highly conserved and there is a small physicochemical difference between isoleucine and valine. This variant is not present in population databases (ExAC no frequency).

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.093
BayesDel_addAF	Uncertain	0.16	D
BayesDel_noAF	Uncertain	-0.010
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.52	D
Eigen	Uncertain	0.21
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.82	T
M_CAP	Uncertain	0.23	D
MetaRNN	Uncertain	0.55	D
MetaSVM	Uncertain	0.65	D
MutationAssessor	Benign	-0.26	N
PhyloP100		9.3
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-0.67	N
REVEL	Uncertain	0.57
Sift	Benign	0.12	T
Sift4G	Benign	0.56	T
Vest4		0.54
ClinPred		0.97	D
GERP RS		5.4
Varity_R		0.31
gMVP		0.23
Mutation Taster		=52/48	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs794728963; hg19: chr1-236898937;