rs80338947

Variant names:

• chr13-20189221-TCTC-T
• rs80338947
• NM_004004.6:c.358_360delGAG

Variant summary

Our verdict is Pathogenic. The variant received 15 ACMG points: 15P and 0B. PS3 PM1 PM4_Supporting PP5_Very_Strong

The NM_004004.6(GJB2):​c.358_360delGAG​(p.Glu120del) variant causes a conservative inframe deletion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000483 in 1,613,638 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV000698248: Functional study showed GJB2 p.glu120del could not for homotypic gap-junction channels, thus lose the junctional conductance (Bruzzone_2003)." and additional evidence is available in ClinVar. The gene GJB2 is included in the ClinGen Criteria Specification Registry.

• Frequency:
  • Genomes: 𝑓 0.000085 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000044 (0 hom.)
• Consequence: GJB2 NM_004004.6 conservative_inframe_deletion
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:22 O:1
• Conservation: PhyloP100: 3.30
• Publications: 29 publications found

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

ENSG00000296095 (HGNC:):

ACMG classification

Specifications for GJB2 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Pathogenic. The variant received 15 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV000698248: Functional study showed GJB2 p.glu120del could not for homotypic gap-junction channels, thus lose the junctional conductance (Bruzzone_2003).; SCV000914613: Functional studies conducted by two independent laboratories in Xenopus oocytes and HeLa cells revealed that compared with the wild type protein and negative control, the p.Glu120del variant resulted in the loss of gap junction channel function (Bruzzone et al. 2003; Mani et al. 2009).; SCV002059938: GJB2 c.358_360delGAG, p.E120del was previously shown to be deficient in inducing formation of junctional channels (PMID: 18941476).; SCV000061503: Functional studies indicate that the channels formed by the p.Glu120del mutant protein are inactive (Mani 2008).; SCV000617686: Published functional studies demonstrate c.358_360delGAG impairs the function of gap channels (Bruzzone et al., 2003; Mani et al., 2009); SCV000945066: Experimental studies have shown that this variant affects GJB2 function (PMID: 12505163, 18941476).; SCV001434017: Functional studies showed that p.Glu120del mutant did not induce the formation of homotypic junctional channel since the conductance levels measured did not exceed the background levels in Xenopus laevis oocytes (PMID:12505163). Besides, no dye transfer (Lucifer Yellow) was observed when p.Glu120del mutant was tested in HeLa cells (PMID:18941476).
• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 8 uncertain in NM_004004.6
• PM4: Nonframeshift variant in NON repetitive region in NM_004004.6. Strenght limited to Supporting due to length of the change: 1aa.
• PP5: Variant 13-20189221-TCTC-T is Pathogenic according to our data. Variant chr13-20189221-TCTC-T is described in ClinVar as Pathogenic. ClinVar VariationId is 17006.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.358_360delGAG	p.Glu120del	conservative_inframe_deletion	Exon 2 of 2	NP_003995.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GJB2	ENST00000382848.5	TSL:1 MANE Select	c.358_360delGAG	p.Glu120del	conservative_inframe_deletion	Exon 2 of 2	ENSP00000372299.4	P29033
	GJB2	ENST00000382844.2	TSL:6	c.358_360delGAG	p.Glu120del	conservative_inframe_deletion	Exon 1 of 1	ENSP00000372295.1	P29033
	GJB2	ENST00000906230.1		c.358_360delGAG	p.Glu120del	conservative_inframe_deletion	Exon 2 of 2	ENSP00000576289.1

Frequencies

GnomAD3 genomes AF: 0.0000854 AC: 13 AN: 152212 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000162

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000719 AC: 18 AN: 250256 AF XY: 0.0000665

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: 0.000133

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000445 AC: 65 AN: 1461426 Hom.: 0 AF XY: 0.0000413 AC XY: 30 AN XY: 727020

African (AFR) AF: 0.0000299 AC: 1 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: 0.000139 AC: 12 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52958

Middle Eastern (MID) AF: 0.000173 AC: 1 AN: 5768

European-Non Finnish (NFE) AF: 0.0000432 AC: 48 AN: 1112006

Other (OTH) AF: 0.0000497 AC: 3 AN: 60396

GnomAD4 genome AF: 0.0000854 AC: 13 AN: 152212 Hom.: 0 Cov.: 32 AF XY: 0.0000807 AC XY: 6 AN XY: 74374

African (AFR) AF: 0.0000483 AC: 2 AN: 41450

American (AMR) AF: 0.00 AC: 0 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.000162 AC: 11 AN: 68034

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.000174 Hom.: 0

Bravo AF: 0.0000793

EpiCase AF: 0.000109

EpiControl AF: 0.000237

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
11	-	-	Autosomal recessive nonsyndromic hearing loss 1A (12)
5	-	-	not provided (5)
1	-	-	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)
1	-	-	Hearing impairment (1)
1	-	-	Hearing loss (1)
1	-	-	Monogenic hearing loss (1)
1	-	-	Nonsyndromic genetic hearing loss (1)
1	-	-	Rare genetic deafness (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		3.3
Mutation Taster		=56/44	disease causing (ClinVar)

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

dbSNP: rs80338947; hg19: chr13-20763360;