rs1553255336

Variant names:

• chr1-229431742-TGCCAGC-T
• rs1553255336
• NM_001100.4:c.963_968delGCTGGC

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1 PM2 PM4 PP3

The NM_001100.4(ACTA1):​c.963_968delGCTGGC​(p.Leu322_Ala323del) variant causes a disruptive inframe deletion change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. A321A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ACTA1 NM_001100.4 disruptive_inframe_deletion
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.94

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]

ENSG00000290037 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a hotspot region, there are 2 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
• PM4: Nonframeshift variant in NON repetitive region in NM_001100.4.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTA1	NM_001100.4	c.963_968delGCTGGC	p.Leu322_Ala323del	disruptive_inframe_deletion	Exon 6 of 7	ENST00000366684.7	NP_001091.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACTA1	ENST00000366684.7	c.963_968delGCTGGC	p.Leu322_Ala323del	disruptive_inframe_deletion	Exon 6 of 7	1	NM_001100.4	ENSP00000355645.3
ACTA1	ENST00000366683.4	c.963_968delGCTGGC	p.Leu322_Ala323del	disruptive_inframe_deletion	Exon 6 of 7	5		ENSP00000355644.4
ACTA1	ENST00000684723.1	c.828_833delGCTGGC	p.Leu277_Ala278del	disruptive_inframe_deletion	Exon 5 of 6			ENSP00000508084.1
ENSG00000290037	ENST00000702606.1	n.380_385delCAGCGC		non_coding_transcript_exon_variant	Exon 1 of 1

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Actin accumulation myopathy Uncertain:1

Feb 15, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, this is a novel in-frame deletion with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Experimental studies and prediction algorithms are not available for this variant, and the functional significance of the deleted amino acids is currently unknown. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a ACTA1-related disease. This sequence change deletes 6 nucleotides from exon 6 of the ACTA1 mRNA (c.963_968delGCTGGC). This leads to the deletion of 2 amino acid residue(s) in the ACTA1 protein (p.Leu322_Ala323del) but otherwise preserves the integrity of the reading frame. -

Computational scores

Source: dbNSFP v4.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1553255336; hg19: chr1-229567489;