chr1-229432723-A-G

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1PM5PP2PP3_StrongPP5_Very_Strong

The NM_001100.4(ACTA1):c.287T>C(p.Leu96Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000124 in 1,614,060 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L96V) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

ACTA1
NM_001100.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3

Conservation

PhyloP100: 9.32

Publications

6 publications found

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 Gene-Disease associations (from GenCC):

alpha-actinopathy
Inheritance: AR, AD Classification: DEFINITIVE Submitted by: ClinGen
congenital myopathy 2a, typical, autosomal dominant
Inheritance: AR, SD, AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
congenital myopathy with excess of thin filaments
Inheritance: SD Classification: DEFINITIVE Submitted by: Illumina
congenital myopathy 2c, severe infantile, autosomal dominant
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
childhood-onset nemaline myopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
congenital fiber-type disproportion myopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
intermediate nemaline myopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
progressive scapulohumeroperoneal distal myopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
typical nemaline myopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
rigid spine syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
severe congenital nemaline myopathy
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
zebra body myopathy
Inheritance: Unknown Classification: SUPPORTIVE Submitted by: Orphanet

ACTA1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 17 ACMG points.

PM1

In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_001100.4

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-229432724-G-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1348211.Status of the report is criteria_provided_single_submitter, 1 stars.

PP2

Missense variant in the ACTA1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 154 curated pathogenic missense variants (we use a threshold of 10). The gene has 0 curated benign missense variants. Gene score misZ: 4.5292 (above the threshold of 3.09). Trascript score misZ: 6.088 (above the threshold of 3.09). GenCC associations: The gene is linked to congenital myopathy with excess of thin filaments, congenital fiber-type disproportion myopathy, severe congenital nemaline myopathy, congenital myopathy 2a, typical, autosomal dominant, zebra body myopathy, alpha-actinopathy, rigid spine syndrome, progressive scapulohumeroperoneal distal myopathy, childhood-onset nemaline myopathy, typical nemaline myopathy, intermediate nemaline myopathy, congenital myopathy 2c, severe infantile, autosomal dominant.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.988

PP5

Variant 1-229432723-A-G is Pathogenic according to our data. Variant chr1-229432723-A-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 18279.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTA1	NM_001100.4 link	c.287T>C	p.Leu96Pro	missense_variant	Exon 3 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.287T>C	p.Leu96Pro	missense_variant	Exon 3 of 7	1	NM_001100.4	ENSP00000355645.3	P68133
ACTA1	ENST00000366683.4 link	c.287T>C	p.Leu96Pro	missense_variant	Exon 3 of 7	5		ENSP00000355644.4	A6NL76
ACTA1	ENST00000684723.1 link	c.152T>C	p.Leu51Pro	missense_variant	Exon 2 of 6			ENSP00000508084.1	A0A804HKV3

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152168

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.0000123

AC:

AN:

1461892

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000153

AC:

AN:

1112012

Other (OTH)

AF:

0.0000166

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.461

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:

0.0000131

AC:

AN:

152168

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74330

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

41436

American (AMR)

AF:

0.00

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Actin accumulation myopathy

Pathogenic:1

Aug 09, 2022

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. Experimental studies have shown that this missense change affects ACTA1 function (PMID: 15226407). 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 ACTA1 protein function. ClinVar contains an entry for this variant (Variation ID: 18279). This variant is also known as Leu94Pro, L94P. This missense change has been observed in individual(s) with autosomal recessive nemaline myopathy (PMID: 10508519). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 96 of the ACTA1 protein (p.Leu96Pro). -

Congenital myopathy 2b, severe infantile, autosomal recessive

Pathogenic:1

Oct 01, 1999

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

ACTA1-related myopathies

Pathogenic:1

Aug 28, 2020

Rady Children's Institute for Genomic Medicine, Rady Children's Hospital San Diego

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is historically referred to as p.Leu94Pro in the literature (PMID: 15226407, 10508519). This variant has been previously reported as a compound heterozygous change in-trans configuration with another missense variant (c.782A>T, p.Glu259Val) in two siblings with severe nemaline myopathy, and it was present in the heterozygous state in their unaffected sibling and parent (PMID: 15226407). In vitro studies using reticulocyte lysates showed that the mutant p.Leu96Pro (named L94P) (as well as the p.Glu259Val, named E259V) remained bound to cytosolic chaperonin (CCT) and prefoldin, and demonstrated absent folded actin (PMID: 10508519). The c.287T>C (p.Leu96Pro) variant is absent from the gnomAD population database and thus is presumed to be rare. This variant affects a highly conserved amino acid and is predicted by multiple in silico tools to have a deleterious effect on protein function. Based on the available evidence, the c.287T>C (p.Leu96Pro) variant is classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.56

BayesDel_noAF

Pathogenic

0.56

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.99

D;D

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.84

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.95

D;D

M_CAP

Pathogenic

0.66

MetaRNN

Pathogenic

0.99

D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

5.3

H;.

PhyloP100

9.3

PrimateAI

Pathogenic

0.91

PROVEAN

Pathogenic

-5.1

D;D

REVEL

Pathogenic

0.91

Sift

Uncertain

0.0030

.;D

Sift4G

Pathogenic

0.0

D;D

Polyphen

1.0

D;.

Vest4

0.99

MutPred

0.92

Gain of disorder (P = 0.0087);Gain of disorder (P = 0.0087);

MVP

0.99

ClinPred

1.0

GERP RS

4.7

Varity_R

1.0

gMVP

1.0

Mutation Taster

=1/99

disease causing (ClinVar)

(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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over