rs372686280

Variant summary

Our verdict is Pathogenic. Variant got 8 ACMG points: 8P and 0B. PM3_StrongPVS1_Strong

This summary comes from the ClinGen Evidence Repository: The variant c.990+1G>T in ACTA1 occurs within the canonical splice donor site (+1) of intron 6. It is predicted to cause skipping of biologically-relevant-exon resulting in an out of frame deletion. However, it is predicted to escape nonsense mediated decay and remove >10% of the protein (PVS1_Strong). The highest minor allele frequency in gnomAD v4.1.0 is 0.00001883 (31/1180028 alleles) in the European (non-Finnish) population (no population codes met). This variant has been reported in trans with a pathogenic variant in two probands with nemaline myopathy (PMID:19562689, LOVD (https://www.dmd.nl/)), and homozygous in one proband with nemaline myopathy (https://helda.helsinki.fi/handle/10138/157180) which meets PM3_Strong. In summary, the variant meets the criteria to be classified as pathogenic for autosomal recessive alpha-actinopathy. ACMG/AMP criteria met, as specified by the ClinGen Congenital Myopathies VCEP: PVS1_Strong, PM3_Strong (ClinGen Congenital Myopathies VCEP specifications version 1; 08/07/2024). LINK:https://erepo.genome.network/evrepo/ui/classification/CA1442746/MONDO:0100084/169

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

ACTA1
NM_001100.4 splice_donor, intron

Scores

4
2
1
Splicing: ADA: 1.000
2

Clinical Significance

Pathogenic reviewed by expert panel P:5

Conservation

PhyloP100: 7.68
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 8 ACMG points.

PVS1
For more information check the summary or visit ClinGen Evidence Repository.
PM3
For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
ACTA1NM_001100.4 linkc.990+1G>T splice_donor_variant, intron_variant Intron 6 of 6 ENST00000366684.7 NP_001091.1 P68133

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
ACTA1ENST00000366684.7 linkc.990+1G>T splice_donor_variant, intron_variant Intron 6 of 6 1 NM_001100.4 ENSP00000355645.3 P68133
ACTA1ENST00000366683.4 linkc.990+1G>T splice_donor_variant, intron_variant Intron 6 of 6 5 ENSP00000355644.4 A6NL76
ACTA1ENST00000684723.1 linkc.855+1G>T splice_donor_variant, intron_variant Intron 5 of 5 ENSP00000508084.1 A0A804HKV3
ENSG00000290037ENST00000702606.1 linkn.355C>A non_coding_transcript_exon_variant Exon 1 of 1

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152204
Hom.:
0
Cov.:
32
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:
0.0000441
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.0000119
AC:
3
AN:
251344
Hom.:
0
AF XY:
0.0000147
AC XY:
2
AN XY:
135884
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:
0.0000176
Gnomad OTH exome
AF:
0.000163
GnomAD4 exome
AF:
0.0000212
AC:
31
AN:
1461862
Hom.:
0
Cov.:
31
AF XY:
0.0000220
AC XY:
16
AN XY:
727236
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.0000383
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000252
Gnomad4 OTH exome
AF:
0.0000331
GnomAD4 genome
AF:
0.0000197
AC:
3
AN:
152204
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74352
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000441
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.0000282
Hom.:
0
Bravo
AF:
0.0000189
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.00
AC:
0
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000116
AC:
1
ExAC
AF:
0.00000824
AC:
1
EpiCase
AF:
0.0000545
EpiControl
AF:
0.00

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:5
Revision: reviewed by expert panel
LINK: link

Submissions by phenotype

Actin accumulation myopathy Pathogenic:2
Aug 24, 2016
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change affects a donor splice site in the last intron (intron 6) of the ACTA1 gene. It is expected to disrupt mRNA splicing and likely results in an absent or disrupted protein product. This variant has been reported in an individual affected with severe nemaline myopathy. It was reported to occur in trans with a pathogenic variant (p.Tyr190*) and to be inherited in an autosomal recessive manner (PMID: 19562689). This variant has also been reported in trans with another pathogenic variant (p.Ala146Profs*46) in a second individual affected with nemaline myopathy (http://www.dmd.nl/nmdb). Truncating mutations in ACTA1 are not known to cause autosomal dominant forms of nemaline myopathy (PMID: 12921789, 19562689). Although donor and acceptor splice site variants are typically truncating (PMID: 16199547) and truncating variants in ACTA1 are known to be pathogenic (PMID: 19562689), the pathogenicity of this donor splice site variant in the last intron is not conclusive due to the uncertain impact on mRNA splicing and protein function. Without additional functional and/or genetic data, this variant has been classified as Likely Pathogenic. -

Aug 30, 2019
Baylor Genetics
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This variant was determined to be pathogenic according to ACMG Guidelines, 2015 [PMID:25741868]. -

not provided Pathogenic:2
Sep 28, 2022
GeneDx
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 16199547, 12921789, 25525159, 31589614, 19562689) -

Jan 01, 2022
CeGaT Center for Human Genetics Tuebingen
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Alpha-actinopathy Pathogenic:1
Aug 07, 2024
ClinGen Congenital Myopathies Variant Curation Expert Panel, ClinGen
Significance: Pathogenic
Review Status: reviewed by expert panel
Collection Method: curation

The variant c.990+1G>T in ACTA1 occurs within the canonical splice donor site (+1) of intron 6. It is predicted to cause skipping of biologically-relevant-exon resulting in an out of frame deletion. However, it is predicted to escape nonsense mediated decay and remove >10% of the protein (PVS1_Strong). The highest minor allele frequency in gnomAD v4.1.0 is 0.00001883 (31/1180028 alleles) in the European (non-Finnish) population (no population codes met). This variant has been reported in trans with a pathogenic variant in two probands with nemaline myopathy (PMID:19562689, LOVD (https://www.dmd.nl/)), and homozygous in one proband with nemaline myopathy (https://helda.helsinki.fi/handle/10138/157180) which meets PM3_Strong. In summary, the variant meets the criteria to be classified as pathogenic for autosomal recessive alpha-actinopathy. ACMG/AMP criteria met, as specified by the ClinGen Congenital Myopathies VCEP: PVS1_Strong, PM3_Strong (ClinGen Congenital Myopathies VCEP specifications version 1; 08/07/2024). -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.59
D
BayesDel_noAF
Pathogenic
0.24
CADD
Pathogenic
36
DANN
Uncertain
0.99
Eigen
Pathogenic
0.95
Eigen_PC
Pathogenic
0.75
FATHMM_MKL
Uncertain
0.96
D
GERP RS
3.6

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.93
SpliceAI score (max)
1.0
Details are displayed if max score is > 0.2
DS_DG_spliceai
0.72
Position offset: 2
DS_DL_spliceai
1.0
Position offset: 1

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.

Other links and lift over

dbSNP: rs372686280; hg19: chr1-229567467; API