chr1-229432557-G-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2BP4_ModerateBP7

The NM_001100.4(ACTA1):​c.453C>T​(p.Thr151=) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,457,812 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. T151T) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 31)
Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

ACTA1
NM_001100.4 splice_region, synonymous

Scores

2
Splicing: ADA: 0.0002790
2

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -0.0410
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]

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.45).
BP7
Synonymous conserved (PhyloP=-0.041 with no splicing effect.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE UniProt
ACTA1NM_001100.4 linkuse as main transcriptc.453C>T p.Thr151= splice_region_variant, synonymous_variant 3/7 ENST00000366684.7

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Appris UniProt
ACTA1ENST00000366684.7 linkuse as main transcriptc.453C>T p.Thr151= splice_region_variant, synonymous_variant 3/71 NM_001100.4 P1
ACTA1ENST00000366683.4 linkuse as main transcriptc.453C>T p.Thr151= splice_region_variant, synonymous_variant 3/75
ACTA1ENST00000684723.1 linkuse as main transcriptc.318C>T p.Thr106= splice_region_variant, synonymous_variant 2/6

Frequencies

GnomAD3 genomes
Cov.:
31
GnomAD3 exomes
AF:
0.00000406
AC:
1
AN:
246562
Hom.:
0
AF XY:
0.00
AC XY:
0
AN XY:
133768
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000546
Gnomad SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000206
AC:
3
AN:
1457812
Hom.:
0
Cov.:
37
AF XY:
0.00000138
AC XY:
1
AN XY:
725090
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.0000252
Gnomad4 SAS exome
AF:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00000180
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
Cov.:
31
Bravo
AF:
0.0000227

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Actin accumulation myopathy Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingInvitaeSep 30, 2021This sequence change affects codon 151 of the ACTA1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the ACTA1 protein. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with ACTA1-related disease. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing, but this prediction has not been confirmed by published transcriptional studies. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_noAF
Benign
-0.45
CADD
Benign
12
DANN
Benign
0.86

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Benign
0.00028
dbscSNV1_RF
Benign
0.062
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.

Other links and lift over

dbSNP: rs76030344; hg19: chr1-229568304; API