13-20189605-T-G

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 0 ACMG points: 4P and 4B. BS1PS3_SupportingPP1PM3

This summary comes from the ClinGen Evidence Repository: The filtering allele frequency of the c.-22-2A>C variant in the GJB2 gene is 0.35% for Ashkenazi Jewish chromosomes in gnomAD v2.1.1 (95% CI of 47/10344), which meets the allele frequency threshold defined by the ClinGen Hearing Loss Expert Panel for considering strong evidence against pathogenicity for autosomal recessive hearing loss variants (BS1). However, based on the evidence outlined below, the ClinGen Hearing Loss Expert Panel believes that the evidence for the pathogenicity of this variant for nonsyndromic hearing loss outweighs its high allele frequency in population databases. Therefore, the BS1 code will not contribute to the overall classification. The c.-22-2A>C variant in the GJB2 gene has been detected in at least 9 patients with hearing loss in trans with the pathogenic c.35delG variant (PM3_Very Strong; PMID:25401782, 24039984, 33096615; Invitae internal data, SCV000935680.2; Children’s Hospital of Philadelphia internal data, Molecular Otolaryngology and Renal Research Laboratories internal data) and one individual with the the p.Leu90Pro variant suspected in trans (PMID:19814620). Phase was confirmed in at least 6 of these 10 observations.This variant has been reported to segregate with hearing loss in at least 2 family members (PP1; PMID:24039984). It was also identified in the heterozygous state without a second variant in 8 individuals with hearing loss, and in the biallelic state (with c.35delG) in one individual with reportedly normal hearing (GeneDx, ARUP internal data, SCV000680741.2, SCV000603828.1). Of note, the severity of hearing loss is reported to be mild-moderate in affected probands, some with onset in the third to fourth decade, suggesting that this variant may be a hypomorphic allele. RNA analysis using patient cells demonstrated that the c.-22-2A>C variant leads to expression of a novel GJB2 transcript with a slightly longer 5' UTR but otherwise normal coding region. The alternate transcript was shown to have reduced expression, but it is not clear if the lower expression is sufficient to lead to a phenotype (PS3_Supporting; PMID:24039984). In summary, the VCEP has used expert judgement to classify this variant as likely pathogenic for autosomal recessive hearing loss based on the ACMG/AMP criteria applied, as specified by the Hearing Loss Expert Panel: PM3_Very Strong, PP1, PS3_Supporting, BS1. LINK:https://erepo.genome.network/evrepo/ui/classification/CA6904346/MONDO:0019497/005

Frequency

Genomes: 𝑓 0.00058 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00071 ( 2 hom. )

Consequence

GJB2
NM_004004.6 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Likely pathogenic reviewed by expert panel P:19U:2B:2

Conservation

PhyloP100: 6.71

Publications

17 publications found

Variant links:

Genes affected

GJB2 (HGNC:4284): (gap junction protein beta 2) This gene encodes a member of the gap junction protein family. The gap junctions were first characterized by electron microscopy as regionally specialized structures on plasma membranes of contacting adherent cells. These structures were shown to consist of cell-to-cell channels that facilitate the transfer of ions and small molecules between cells. The gap junction proteins, also known as connexins, purified from fractions of enriched gap junctions from different tissues differ. According to sequence similarities at the nucleotide and amino acid levels, the gap junction proteins are divided into two categories, alpha and beta. Mutations in this gene are responsible for as much as 50% of pre-lingual, recessive deafness. [provided by RefSeq, Oct 2008]

GJB2 Gene-Disease associations (from GenCC):

Bart-Pumphrey syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
ichthyosis, hystrix-like, with hearing loss
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp
keratoderma hereditarium mutilans
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Genomics England PanelApp
palmoplantar keratoderma-deafness syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, G2P
syndromic genetic hearing loss
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
autosomal recessive nonsyndromic hearing loss 1A
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine
nonsyndromic genetic hearing loss
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
autosomal dominant keratitis-ichthyosis-hearing loss syndrome
Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Genomics England PanelApp
autosomal dominant nonsyndromic hearing loss 3A
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
autosomal dominant nonsyndromic hearing loss
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
KID syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
hearing loss, autosomal recessive
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

GJB2 links:

ENSG00000296095 (HGNC:):

ENSG00000296095 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 0 ACMG points.

PS3

For more information check the summary or visit ClinGen Evidence Repository.

PM3

For more information check the summary or visit ClinGen Evidence Repository.

PP1

For more information check the summary or visit ClinGen Evidence Repository.

BS1

For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004004.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GJB2	NM_004004.6	MANE Select	c.-22-2A>C		splice_acceptor intron	N/A	NP_003995.2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
GJB2	ENST00000382848.5	TSL:1 MANE Select	c.-22-2A>C	splice_acceptor intron	N/A	ENSP00000372299.4	P29033
GJB2	ENST00000382844.2	TSL:6	c.-24A>C	5_prime_UTR	Exon 1 of 1	ENSP00000372295.1	P29033
GJB2	ENST00000906230.1		c.-24A>C	5_prime_UTR	Exon 2 of 2	ENSP00000576289.1

Frequencies

GnomAD3 genomes

AF:

0.000578

AC:

AN:

152182

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000965

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000916

Gnomad ASJ

AF:

0.00490

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000764

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.000607

AC:

151

AN:

248874

AF XY:

0.000704

show subpopulations

Gnomad AFR exome

AF:

0.0000617

Gnomad AMR exome

AF:

0.000231

Gnomad ASJ exome

AF:

0.00458

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.000827

Gnomad OTH exome

AF:

0.000490

GnomAD4 exome

AF:

0.000710

AC:

1034

AN:

1455754

Hom.:

Cov.:

AF XY:

0.000723

AC XY:

524

AN XY:

724646

show subpopulations

African (AFR)

AF:

0.000150

AC:

AN:

33350

American (AMR)

AF:

0.000447

AC:

AN:

44714

Ashkenazi Jewish (ASJ)

AF:

0.00425

AC:

111

AN:

26098

East Asian (EAS)

AF:

0.00

AC:

AN:

39672

South Asian (SAS)

AF:

0.00

AC:

AN:

86116

European-Finnish (FIN)

AF:

0.0000187

AC:

AN:

53398

Middle Eastern (MID)

AF:

0.000369

AC:

AN:

5422

European-Non Finnish (NFE)

AF:

0.000753

AC:

834

AN:

1106836

Other (OTH)

AF:

0.00101

AC:

AN:

60148

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

Heterozygous variant carriers

122

182

243

304

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

102

136

170

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000578

AC:

AN:

152300

Hom.:

Cov.:

AF XY:

0.000550

AC XY:

AN XY:

74480

show subpopulations

African (AFR)

AF:

0.0000962

AC:

AN:

41562

American (AMR)

AF:

0.000915

AC:

AN:

15304

Ashkenazi Jewish (ASJ)

AF:

0.00490

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000764

AC:

AN:

68020

Other (OTH)

AF:

0.000473

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.495

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000690

Hom.:

Bravo

AF:

0.000608

ClinVar

ClinVar submissions

Significance:Likely pathogenic

Revision:reviewed by expert panel

View on ClinVar

Pathogenic

VUS

Benign

Condition

Autosomal recessive nonsyndromic hearing loss 1A (9)

not provided (6)

Nonsyndromic genetic hearing loss (2)

Autosomal dominant keratitis-ichthyosis-hearing loss syndrome;C0265964:Mutilating keratoderma;C0266004:Knuckle pads, deafness AND leukonychia syndrome;C1835672:Palmoplantar keratoderma-deafness syndrome;C1865234:Ichthyosis, hystrix-like, with hearing loss;C2673759:Autosomal recessive nonsyndromic hearing loss 1A;C2675750:Autosomal dominant nonsyndromic hearing loss 3A (1)

Autosomal dominant nonsyndromic hearing loss 3A (1)

GJB2-related disorder (1)

Ichthyosis, hystrix-like, with hearing loss (1)

Mutilating keratoderma;C0266004:Knuckle pads, deafness AND leukonychia syndrome;C1835672:Palmoplantar keratoderma-deafness syndrome (1)

not specified (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.45

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

PhyloP100

6.7

PromoterAI

-0.021

Neutral

(source)

Mutation Taster

=56/244

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.92

SpliceAI score (max)

0.91

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.23

Position offset: 36

DS_AL_spliceai

0.91

Position offset: -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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over