Genetic Variant USH2A:p.Gly1668ValfsTer12 (chr1-216084863-CT-C) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_206933.4(USH2A):c.5001delA(p.Gly1668ValfsTer12) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,846 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

USH2A
NM_206933.4 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 0.661

Publications

1 publications found

Variant links:

Genes affected

USH2A (HGNC:12601): (usherin) This gene encodes a protein that contains laminin EGF motifs, a pentaxin domain, and many fibronectin type III motifs. The protein is found in the basement membrane, and may be important in development and homeostasis of the inner ear and retina. Mutations within this gene have been associated with Usher syndrome type IIa and retinitis pigmentosa. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Dec 2008]

USH2A links:

USH2A-AS2 (HGNC:40605): (USH2A antisense RNA 2)

USH2A-AS2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-216084863-CT-C is Pathogenic according to our data. Variant chr1-216084863-CT-C is described in ClinVar as Pathogenic. ClinVar VariationId is 2715441.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
USH2A	NM_206933.4 link	c.5001delA	p.Gly1668ValfsTer12	frameshift_variant	Exon 25 of 72	ENST00000307340.8	NP_996816.3	O75445-1
USH2A-AS2	NR_125992.1 link	n.266-1854delT		intron_variant	Intron 2 of 2
USH2A-AS2	NR_125993.1 link	n.137-1854delT		intron_variant	Intron 1 of 1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
USH2A	ENST00000307340.8 link	c.5001delA	p.Gly1668ValfsTer12	frameshift_variant	Exon 25 of 72	1	NM_206933.4	ENSP00000305941.3		O75445-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1460846

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726762

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33428

American (AMR)

AF:

0.00

AC:

AN:

44614

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26104

East Asian (EAS)

AF:

0.00

AC:

AN:

39676

South Asian (SAS)

AF:

0.00

AC:

AN:

86246

European-Finnish (FIN)

AF:

0.0000188

AC:

AN:

53318

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5754

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111372

Other (OTH)

AF:

0.00

AC:

AN:

60334

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.275

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Jun 15, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Gly1668Valfs*12) in the USH2A gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in USH2A are known to be pathogenic (PMID: 10729113, 10909849, 20507924, 25649381). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with USH2A-related conditions. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

0.66

Mutation Taster

=0/200

disease causing (fs/PTC)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over