17-81511470-C-T

Position:

• chr17-81511470-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_001614.5(ACTG1):​c.520G>A​(p.Ala174Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,542 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A174G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: ACTG1 NM_001614.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.53

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 3 uncertain in NM_001614.5
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, ACTG1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.963

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ACTG1	NM_001614.5	c.520G>A	p.Ala174Thr	missense_variant	4/6	ENST00000573283.7
ACTG1	NM_001199954.3	c.520G>A	p.Ala174Thr	missense_variant	4/6
ACTG1	NR_037688.3	n.592G>A		non_coding_transcript_exon_variant	4/7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ACTG1	ENST00000573283.7	c.520G>A	p.Ala174Thr	missense_variant	4/6	5	NM_001614.5	P4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461542 Hom.: 0 Cov.: 37 AF XY: 0.00 AC XY: 0 AN XY: 727072

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal dominant nonsyndromic hearing loss 20 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Oct 19, 2020

Based on the classification scheme VCGS_Germline_v1.1.1, this variant is classified as 3B-VUS. Following criteria are met: 0101 - Gain-of-function is a known mechanism of disease for this gene. (N) 0107 - This gene is known to be associated with autosomal dominant disease. (N) 0200 - Variant is predicted to result in a missense amino acid change from alanine to threonine (exon 4). (N) 0251 - Variant is heterozygous. (N) 0301 - Variant is absent from gnomAD. (P) 0309 - An alternative amino acid change at the same position has been observed in gnomAD v2 (1 heterozygote, 0 homozygotes). (N) 0502 - Missense variant with conflicting in silico predictions and/or uninformative conservation. (N) 0603 - Missense variant in a region that is highly intolerant to missense variation (high constraint region) (actin domain; PDB). (P) 0705 - No comparable variants have previous evidence for pathogenicity. Alternative changes at the same residue (p.Ala174Ser, p.Ala174Gly) have been reported as VUS (ClinVar, deafnessvariationdatabase, LOVD, PMID: 29907799). (N) 0807 - Variant has not previously been reported in a clinical context. (N) 0905 - No segregation evidence has been identified for this variant. (N) 1007 - No published functional evidence has been identified for this variant. (N) 1208 - Inheritance information for this variant is not currently available. (N) Legend: (P) - Pathogenic, (N) - Neutral, (B) - Benign -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
CADD	Pathogenic	26
DANN	Benign	0.95
DEOGEN2	Pathogenic	0.91	D;D;D;D;D;D;D;D;D
Eigen	Benign	0.18
Eigen_PC	Uncertain	0.27
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.96	D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.88	D
MutationAssessor	Uncertain	2.9	M;M;M;M;M;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Pathogenic	0.81	D
Sift4G	Uncertain	0.060	T;T;T;T;T;.;.;.;D
Polyphen		0.0010	B;B;B;B;B;B;.;.;.
Vest4		0.88
MutPred		0.81		Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);.;Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);
MVP		0.93
ClinPred		0.99	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.93
gMVP		0.98

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr17-79478496;