rs1555666715

Variant names:

• chr17-81511373-C-T
• rs1555666715
• NM_001614.5:c.617G>A

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_001614.5(ACTG1):​c.617G>A​(p.Arg206Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,618 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R206W) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ACTG1 NM_001614.5 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.48
• 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: Pathogenic. The variant received 16 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_001614.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-81511374-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 864856.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.936
• PP5: Variant 17-81511373-C-T is Pathogenic according to our data. Variant chr17-81511373-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 517300.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACTG1	NM_001614.5	c.617G>A	p.Arg206Gln	missense_variant	Exon 4 of 6	ENST00000573283.7	NP_001605.1
ACTG1	NM_001199954.3	c.617G>A	p.Arg206Gln	missense_variant	Exon 4 of 6		NP_001186883.1
ACTG1	NR_037688.3	n.689G>A		non_coding_transcript_exon_variant	Exon 4 of 7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACTG1	ENST00000573283.7	c.617G>A	p.Arg206Gln	missense_variant	Exon 4 of 6	5	NM_001614.5	ENSP00000458435.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250910 AF XY: 0.00000737

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461618 Hom.: 0 Cov.: 37 AF XY: 0.00000138 AC XY: 1 AN XY: 727130

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53156

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112008

Other (OTH) AF: 0.00 AC: 0 AN: 60388

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Oct 26, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt ACTG1 protein function. ClinVar contains an entry for this variant (Variation ID: 517300). This missense change has been observed in individual(s) with deafness (Invitae). In at least one individual the variant was observed to be de novo. This variant is present in population databases (no rsID available, gnomAD 0.0009%). This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 206 of the ACTG1 protein (p.Arg206Gln). -

Baraitser-winter syndrome 2 Pathogenic:1

Sep 29, 2022

Sangiuolo Lab - Medical Genetics Laboratory, Tor Vergata University

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Rare genetic deafness Pathogenic:1

Aug 10, 2017

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Arg206Gln variant in ACTG1 has now been identified by our laboratory to ha ve occurred de novo in 1 individual with congenital progressive sensorineural he aring loss and vestibular dysfunction. This variant has been identified in 1/111 396 European chromosomes by the Genome Aggregation Database (gnomAD, http://gnom ad.broadinstitute.org). Please note that for diseases with clinical variability , reduced penetrance, or recessive inheritance, pathogenic variants may be prese nt at a low frequency in the general population. Computational prediction tools and conservation analysis suggest that the p.Arg206Gln variant may impact the pr otein, though this information is not predictive enough to determine pathogenici ty. Missense variants in the ACTG1 gene have been associated with two condition s: 1) Autosomal dominant progressive hearing loss and vestibular dysfunction (de Heer 2009); 2) Baraitser-Winter syndrome. In summary, though additional studies are required to fully establish its clinical significance, the p.Arg206Gln vari ant is likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.88	D;D;D;D;D;D;D;T;T
Eigen	Uncertain	0.23
Eigen_PC	Uncertain	0.30
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.96	.;.;D;.;.;.;D;.;D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.94	D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.79	D
MutationAssessor	Benign	1.9	M;M;M;M;M;M;.;.;.
PhyloP100		7.5
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-2.5	.;D;.;.;.;.;.;.;.
REVEL	Pathogenic	0.85
Sift4G	Benign	0.080	T;T;T;T;T;.;.;.;T
Polyphen		0.0020	B;B;B;B;B;B;.;.;.
Vest4		0.82
MutPred		0.75		Gain of glycosylation at T203 (P = 0.0803);Gain of glycosylation at T203 (P = 0.0803);Gain of glycosylation at T203 (P = 0.0803);Gain of glycosylation at T203 (P = 0.0803);Gain of glycosylation at T203 (P = 0.0803);Gain of glycosylation at T203 (P = 0.0803);.;Gain of glycosylation at T203 (P = 0.0803);Gain of glycosylation at T203 (P = 0.0803);
MVP		0.96
ClinPred		0.93	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.89
gMVP		0.97
Mutation Taster		=19/81	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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

dbSNP: rs1555666715; hg19: chr17-79478399;