Genetic Variant ACTA1:p.Tyr220* (chr1-229432142-G-T) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_001100.4(ACTA1):c.660C>A(p.Tyr220*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000616 in 1,461,276 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 Pathogenic (★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

ACTA1
NM_001100.4 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: -0.0900

Variant links:

Genes affected

ACTA1 (HGNC:129): (actin alpha 1, skeletal muscle) The product encoded by this gene belongs to the actin family of proteins, which are highly conserved proteins that play a role in cell motility, structure and integrity. Alpha, beta and gamma actin isoforms have been identified, with alpha actins being a major constituent of the contractile apparatus, while beta and gamma actins are involved in the regulation of cell motility. This actin is an alpha actin that is found in skeletal muscle. Mutations in this gene cause a variety of myopathies, including nemaline myopathy, congenital myopathy with excess of thin myofilaments, congenital myopathy with cores, and congenital myopathy with fiber-type disproportion, diseases that lead to muscle fiber defects with manifestations such as hypotonia. [provided by RefSeq, Sep 2019]

ACTA1 links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-229432142-G-T is Pathogenic according to our data. Variant chr1-229432142-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 464130.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTA1	NM_001100.4 link	c.660C>A	p.Tyr220*	stop_gained	Exon 5 of 7	ENST00000366684.7	NP_001091.1	P68133

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
ACTA1	ENST00000366684.7 link	c.660C>A	p.Tyr220*	stop_gained	Exon 5 of 7	1	NM_001100.4	ENSP00000355645.3	P68133
ACTA1	ENST00000366683.4 link	c.660C>A	p.Tyr220*	stop_gained	Exon 5 of 7	5		ENSP00000355644.4	A6NL76
ACTA1	ENST00000684723.1 link	c.525C>A	p.Tyr175*	stop_gained	Exon 4 of 6			ENSP00000508084.1	A0A804HKV3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000120

AC:

AN:

250822

Hom.:

AF XY:

0.00000737

AC XY:

AN XY:

135710

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000265

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000616

AC:

AN:

1461276

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

726948

show subpopulations

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:

0.0000187

Gnomad4 NFE exome

AF:

0.00000720

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Actin accumulation myopathy

Pathogenic:1

May 07, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 464130). This variant has not been reported in the literature in individuals affected with ACTA1-related conditions. This variant is present in population databases (rs201823652, gnomAD 0.003%). This sequence change creates a premature translational stop signal (p.Tyr220*) in the ACTA1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ACTA1 are known to be pathogenic (PMID: 19562689). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.55

BayesDel_noAF

Pathogenic

0.48

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Benign

0.16

Eigen_PC

Benign

-0.063

FATHMM_MKL

Benign

0.61

Vest4

0.97

GERP RS

1.3

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over