rs74897770

Positions:

• chr1-229431637-G-T

Variant summary

Our verdict is Benign. Variant got -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BA1

The NM_001100.4(ACTA1):​c.996C>A​(p.Ile332=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00324 in 1,613,834 control chromosomes in the GnomAD database, including 164 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.018 (78 hom., cov: 32)
  • Exomes 𝑓: 0.0017 (86 hom.)
• Consequence: ACTA1 NM_001100.4 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:9
• Conservation: PhyloP100: 1.23

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]

(HGNC:):

ACMG classification

Verdict is Benign. Variant got -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.58).
• BP6: Variant 1-229431637-G-T is Benign according to our data. Variant chr1-229431637-G-T is described in ClinVar as [Likely_benign]. Clinvar id is 93555.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-229431637-G-T is described in Lovd as [Benign].
• BP7: Synonymous conserved (PhyloP=1.23 with no splicing effect.
• BA1: GnomAd4 highest subpopulation (AFR) allele frequency at 95% confidence interval = 0.0599 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ACTA1	NM_001100.4	c.996C>A	p.Ile332=	synonymous_variant	7/7	ENST00000366684.7	NP_001091.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ACTA1	ENST00000366684.7	c.996C>A	p.Ile332=	synonymous_variant	7/7	1	NM_001100.4	ENSP00000355645	P1
	ENST00000702606.1	n.272G>T		non_coding_transcript_exon_variant	1/1
ACTA1	ENST00000684723.1	c.861C>A	p.Ile287=	synonymous_variant	6/6			ENSP00000508084
ACTA1	ENST00000366683.4	c.991-73C>A		intron_variant		5		ENSP00000355644

Frequencies

GnomAD3 genomes AF: 0.0177 AC: 2691 AN: 151874 Hom.: 78 Cov.: 32

Gnomad AFR AF: 0.0618

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00616

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.000147

Gnomad OTH AF: 0.0144

GnomAD3 exomes AF: 0.00431 AC: 1084 AN: 251442 Hom.: 45 AF XY: 0.00310 AC XY: 421 AN XY: 135902

Gnomad AFR exome AF: 0.0606

Gnomad AMR exome AF: 0.00254

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000653

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.000978

GnomAD4 exome AF: 0.00173 AC: 2531 AN: 1461842 Hom.: 86 Cov.: 31 AF XY: 0.00143 AC XY: 1041 AN XY: 727234

Gnomad4 AFR exome AF: 0.0634

Gnomad4 AMR exome AF: 0.00295

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.000128

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000279

Gnomad4 OTH exome AF: 0.00363

GnomAD4 genome AF: 0.0178 AC: 2700 AN: 151992 Hom.: 78 Cov.: 32 AF XY: 0.0169 AC XY: 1259 AN XY: 74320

Gnomad4 AFR AF: 0.0619

Gnomad4 AMR AF: 0.00615

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000147

Gnomad4 OTH AF: 0.0142

Alfa AF: 0.00811 Hom.: 18

Bravo AF: 0.0193

Asia WGS AF: 0.00549 AC: 19 AN: 3478

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:9

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:4

Benign, criteria provided, single submitter	clinical testing	GeneDx	Nov 15, 2017	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	May 28, 2013	- -
Benign, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	-	- -
Likely benign, no assertion criteria provided	clinical testing	Genetic Services Laboratory, University of Chicago	-	Likely benign based on allele frequency in 1000 Genomes Project or ESP global frequency and its presence in a patient with a rare or unrelated disease phenotype. NOT Sanger confirmed. -

Actin accumulation myopathy Benign:2

Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -
Benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 18, 2024	- -

Congenital myopathy with fiber type disproportion Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

not provided Benign:1

Likely benign, criteria provided, single submitter

not provided

Breakthrough Genomics, Breakthrough Genomics

-

- -

Familial restrictive cardiomyopathy Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.58
CADD	Benign	17
DANN	Benign	0.77

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.16		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

Other links and lift over

dbSNP: rs74897770; hg19: chr1-229567384;