17-81510697-C-T

Variant names:

• chr17-81510697-C-T
• NM_001614.5:c.1121G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001614.5(ACTG1):​c.1121G>A​(p.Cys374Tyr) 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C374S) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ACTG1 NM_001614.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.52
• Publications: 0 publications found

Genes affected

ACTG1 (HGNC:144): (actin gamma 1) Actins are highly conserved proteins that are involved in various types of cell motility and in maintenance of the cytoskeleton. Three main groups of actin isoforms have been identified in vertebrate animals: alpha, beta, and gamma. The alpha actins are found in muscle tissues and are a major constituent of the contractile apparatus. The beta and gamma actins co-exist in most cell types as components of the cytoskeleton and as mediators of internal cell motility. Actin gamma 1, encoded by this gene, is a cytoplasmic actin found in all cell types. Mutations in this gene are associated with DFNA20/26, a subtype of autosomal dominant non-syndromic sensorineural progressive hearing loss and also with Baraitser-Winter syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2017]

ACTG1 Gene-Disease associations (from GenCC):

• Baraitser-winter syndrome 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P, PanelApp Australia
• nonsyndromic genetic hearing loss

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• autosomal dominant nonsyndromic hearing loss 20

  Inheritance: AD Classification: STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae)
• autosomal dominant nonsyndromic hearing loss

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Baraitser-Winter cerebrofrontofacial syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.986

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTG1	NM_001614.5	c.1121G>A	p.Cys374Tyr	missense_variant	Exon 6 of 6	ENST00000573283.7	NP_001605.1
ACTG1	NM_001199954.3	c.1121G>A	p.Cys374Tyr	missense_variant	Exon 6 of 6		NP_001186883.1
ACTG1	NR_037688.3	n.1193G>A		non_coding_transcript_exon_variant	Exon 6 of 7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACTG1	ENST00000573283.7	c.1121G>A	p.Cys374Tyr	missense_variant	Exon 6 of 6	5	NM_001614.5	ENSP00000458435.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal dominant nonsyndromic hearing loss 20;C3281235:Baraitser-winter syndrome 2 Uncertain:1

Nov 28, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with ACTG1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 374 of the ACTG1 protein (p.Cys374Tyr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	29
DANN	Benign	0.95
DEOGEN2	Pathogenic	0.93	D;D;D;D;D;D
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Pathogenic	1.0	.;.;D;.;.;.
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	M;M;M;M;M;M
PhyloP100		7.5
PrimateAI	Pathogenic	0.92	D
PROVEAN	Uncertain	-3.9	.;D;.;.;.;.
REVEL	Pathogenic	0.96
Sift4G	Uncertain	0.013	D;D;D;D;D;.
Polyphen		1.0	D;D;D;D;D;D
Vest4		0.93
MutPred		0.86		Gain of disorder (P = 0.0674);Gain of disorder (P = 0.0674);Gain of disorder (P = 0.0674);Gain of disorder (P = 0.0674);Gain of disorder (P = 0.0674);Gain of disorder (P = 0.0674);
MVP		0.99
ClinPred		1.0	D
GERP RS		3.9
Varity_R		0.96
gMVP		0.97
Mutation Taster		=22/78	disease causing

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

Other links and lift over

hg19: chr17-79477723;