rs121909525

chr1-229431994-C-Achr1-229431994-C-G

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5

The NM_001100.4(ACTA1):c.808G>T(p.Gly270Cys) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G270D) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: ACTA1 NM_001100.4 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 5.93

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]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_001100.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-229431902-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 434074.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, ACTA1
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
• PP5: Variant 1-229431994-C-A is Pathogenic according to our data. Variant chr1-229431994-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 18285.Status of the report is no_assertion_criteria_provided, 0 stars. Variant chr1-229431994-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ACTA1	NM_001100.4	c.808G>T	p.Gly270Cys	missense_variant, splice_region_variant	5/7	ENST00000366684.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ACTA1	ENST00000366684.7	c.808G>T	p.Gly270Cys	missense_variant, splice_region_variant	5/7	1	NM_001100.4	P1
ACTA1	ENST00000366683.4	c.808G>T	p.Gly270Cys	missense_variant, splice_region_variant	5/7	5
ACTA1	ENST00000684723.1	c.673G>T	p.Gly225Cys	missense_variant, splice_region_variant	4/6

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Actin accumulation myopathy Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jun 01, 2001

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.56
Cadd	Pathogenic	34
Dann	Uncertain	0.99
DEOGEN2	Pathogenic	0.99	D
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.76	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	5.1	H
MutationTaster	Benign	1.0	A;A;A;A
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-7.0	D
REVEL	Pathogenic	0.98
Sift4G	Uncertain	0.0080	D
Polyphen		1.0	D
Vest4		0.82
MutPred		0.88		Loss of disorder (P = 0.0347);
MVP		0.99
ClinPred		1.0	D
GERP RS		4.3
Varity_R		0.96
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.020		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: rs121909525; hg19: chr1-229567741;