1-229431503-A-G

Position:

• chr1-229431503-A-G

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5_Moderate

The NM_001100.4(ACTA1):​c.1130T>C​(p.Phe377Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic 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. F377C) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ACTA1 NM_001100.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.27

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 Pathogenic. Variant got 11 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 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 chr1-229431503-A-C is described in Lovd as [Pathogenic].
• PP2: Missense variant where missense usually causes diseases, ACTA1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.924
• PP5: Variant 1-229431503-A-G is Pathogenic according to our data. Variant chr1-229431503-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 692083.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ACTA1	NM_001100.4	c.1130T>C	p.Phe377Ser	missense_variant	7/7	ENST00000366684.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ACTA1	ENST00000366684.7	c.1130T>C	p.Phe377Ser	missense_variant	7/7	1	NM_001100.4	P1
	ENST00000702606.1	n.138A>G		non_coding_transcript_exon_variant	1/1
ACTA1	ENST00000366683.4	c.1052T>C	p.Phe351Ser	missense_variant	7/7	5
ACTA1	ENST00000684723.1	c.995T>C	p.Phe332Ser	missense_variant	6/6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Actin accumulation myopathy Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

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

Mar 08, 2019

This variant has not been previously reported or functionally characterized in the literature to our knowledge. Other variants at this nucleotide position have been reported in two individuals with autosomal dominant nemaline myopathy and variants in this exon are frequently associated with autosomal dominant inheritance (PMID: 16967490, 19562689). It is absent from the ExAC and gnomAD population databases and thus is presumed to be rare. In silico analyses support a deleterious effect of the c.1130T>C (p.Phe377Ser) variant on protein function. Analysis of the parental samples was negative for the variant, indicating this variant likely occurred as a de novo event. Based on the available evidence, the c.1130T>C (p.Phe377Ser) 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	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.93	D;D
Eigen	Pathogenic	0.77
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.92	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.9	M;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.90	D
PROVEAN	Uncertain	-2.9	D;.
REVEL	Pathogenic	0.93
Sift4G	Pathogenic	0.0	D;D
Polyphen		0.96	D;.
Vest4		0.91
MutPred		0.62		Gain of disorder (P = 0.0079);.;
MVP		0.95
ClinPred		1.0	D
GERP RS		3.9
Varity_R		0.96
gMVP		0.99

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

LitVar

Other links and lift over

dbSNP: rs1571892193; hg19: chr1-229567250;