1-236739321-G-T

Variant names:

• chr1-236739321-G-T
• rs746677039
• NM_001103.4:c.896G>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001103.4(ACTN2):​c.896G>T​(p.Arg299Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R299H) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ACTN2 NM_001103.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.99
• Publications: 5 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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.839

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001103.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ACTN2	NM_001103.4	MANE Select	c.896G>T	p.Arg299Leu	missense	Exon 10 of 21	NP_001094.1
	ACTN2	NM_001278343.2		c.896G>T	p.Arg299Leu	missense	Exon 10 of 21	NP_001265272.1
	ACTN2	NR_184402.1		n.1268G>T		non_coding_transcript_exon	Exon 12 of 23

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ACTN2	ENST00000366578.6	TSL:1 MANE Select	c.896G>T	p.Arg299Leu	missense	Exon 10 of 21	ENSP00000355537.4
	ACTN2	ENST00000542672.7	TSL:1	c.896G>T	p.Arg299Leu	missense	Exon 10 of 21	ENSP00000443495.1
	ACTN2	ENST00000682015.1		c.803G>T	p.Arg268Leu	missense	Exon 9 of 20	ENSP00000506961.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251400 AF XY: 0.00000736

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461874 Hom.: 0 Cov.: 67 AF XY: 0.00000138 AC XY: 1 AN XY: 727238

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53402

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112010

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Uncertain	0.13
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.54	D
Eigen	Uncertain	0.65
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.97	D
M_CAP	Benign	0.072	D
MetaRNN	Pathogenic	0.84	D
MetaSVM	Uncertain	-0.26	T
MutationAssessor	Benign	1.9	L
PhyloP100		10
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-5.3	D
REVEL	Uncertain	0.57
Sift	Uncertain	0.0060	D
Sift4G	Uncertain	0.0050	D
Polyphen		0.96	D
Vest4		0.93
MutPred		0.47		Loss of MoRF binding (P = 0.0112)
MVP		0.83
MPC		0.60
ClinPred		0.99	D
GERP RS		5.7
Varity_R		0.66
gMVP		0.71
Mutation Taster		=22/78	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs746677039; hg19: chr1-236902621;