NM_004004.6:c.-23G>T

Variant names:

• chr13-20192783-C-A
• rs786204734
• NM_004004.6:c.-23G>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PP3 PP5

The NM_004004.6(GJB2):​c.-23G>T variant causes a splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000457 in 153,340 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). The gene GJB2 is included in the ClinGen Criteria Specification Registry.

• Frequency:
  • Genomes: 𝑓 0.000039 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00088 (0 hom.)
• Consequence: GJB2 NM_004004.6 splice_region
• Scores: Splicing: ADA: 0.9942
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:7 U:2
• Conservation: PhyloP100: 0.633
• Publications: 8 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: Uncertain_significance. The variant received 2 ACMG points.

• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
• PP5: Variant 13-20192783-C-A is Pathogenic according to our data. Variant chr13-20192783-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 189155.

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.-23G>T		splice_region	Exon 1 of 2	NP_003995.2
	GJB2	NM_004004.6	MANE Select	c.-23G>T		5_prime_UTR	Exon 1 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.-23G>T		splice_region	Exon 1 of 2	ENSP00000372299.4	P29033
	GJB2	ENST00000382848.5	TSL:1 MANE Select	c.-23G>T		5_prime_UTR	Exon 1 of 2	ENSP00000372299.4	P29033
	GJB2	ENST00000906232.1		c.-57G>T		5_prime_UTR_premature_start_codon_gain	Exon 1 of 2	ENSP00000576291.1

Frequencies

GnomAD3 genomes AF: 0.0000394 AC: 6 AN: 152096 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00124

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.000880 AC: 1 AN: 1136 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 712

African (AFR) AF: 0.00 AC: 0 AN: 8

American (AMR) AF: 0.00 AC: 0 AN: 4

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 4

East Asian (EAS) AF: 0.00 AC: 0 AN: 28

South Asian (SAS) AF: 0.00185 AC: 1 AN: 542

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 16

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 2

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 502

Other (OTH) AF: 0.00 AC: 0 AN: 30

GnomAD4 genome AF: 0.0000394 AC: 6 AN: 152204 Hom.: 0 Cov.: 33 AF XY: 0.0000672 AC XY: 5 AN XY: 74414

African (AFR) AF: 0.00 AC: 0 AN: 41568

American (AMR) AF: 0.00 AC: 0 AN: 15300

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5154

South Asian (SAS) AF: 0.00124 AC: 6 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10586

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 292

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67976

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000227

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
2	1	-	Autosomal recessive nonsyndromic hearing loss 1A (3)
2	-	-	Nonsyndromic genetic hearing loss (2)
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 loss (1)
-	1	-	Mutilating keratoderma;C0266004:Knuckle pads, deafness AND leukonychia syndrome;C1835672:Palmoplantar keratoderma-deafness syndrome (1)
1	-	-	Rare genetic deafness (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.67
CADD	Benign	19
DANN	Benign	0.88
PhyloP100		0.63
PromoterAI		-0.42	Neutral
Mutation Taster		=112/188	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Pathogenic	0.90
SpliceAI score (max)		0.12		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: rs786204734; hg19: chr13-20766922;