chr13-20188478-G-A

Variant names:

• chr13-20188478-G-A
• rs112457424
• NM_004004.6:c.*423C>T

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_004004.6(GJB2):​c.*423C>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000316 in 171,110 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00034 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00011 (0 hom.)
• Consequence: GJB2 NM_004004.6 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:3
• Conservation: PhyloP100: -0.245
• Publications: 0 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: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P
• 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, Genomics England PanelApp, G2P
• palmoplantar keratoderma-deafness syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, G2P
• autosomal recessive nonsyndromic hearing loss 1A

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, G2P, PanelApp Australia
• hearing loss, autosomal recessive

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• autosomal dominant keratitis-ichthyosis-hearing loss syndrome

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics
• autosomal dominant nonsyndromic hearing loss 3A

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• autosomal dominant nonsyndromic hearing loss

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• KID syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000296095 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.83).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJB2	NM_004004.6	c.*423C>T		3_prime_UTR_variant	Exon 2 of 2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.*423C>T		3_prime_UTR_variant	Exon 2 of 2		XP_011533351.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GJB2	ENST00000382848.5	c.*423C>T		3_prime_UTR_variant	Exon 2 of 2	1	NM_004004.6	ENSP00000372299.4
GJB2	ENST00000382844.2	c.*423C>T		3_prime_UTR_variant	Exon 1 of 1	6		ENSP00000372295.1
ENSG00000296095	ENST00000736390.1	n.232-2898C>T		intron_variant	Intron 1 of 3

Frequencies

GnomAD3 genomes AF: 0.000309 AC: 47 AN: 152170 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000797

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000192

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000162

Gnomad OTH AF: 0.000478

GnomAD4 exome AF: 0.000106 AC: 2 AN: 18822 Hom.: 0 Cov.: 0 AF XY: 0.000104 AC XY: 1 AN XY: 9584

African (AFR) AF: 0.00 AC: 0 AN: 378

American (AMR) AF: 0.00 AC: 0 AN: 1982

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 370

East Asian (EAS) AF: 0.00 AC: 0 AN: 938

South Asian (SAS) AF: 0.00 AC: 0 AN: 1554

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 664

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 62

European-Non Finnish (NFE) AF: 0.000168 AC: 2 AN: 11898

Other (OTH) AF: 0.00 AC: 0 AN: 976

GnomAD4 genome AF: 0.000341 AC: 52 AN: 152288 Hom.: 0 Cov.: 33 AF XY: 0.000336 AC XY: 25 AN XY: 74470

African (AFR) AF: 0.000915 AC: 38 AN: 41546

American (AMR) AF: 0.0000653 AC: 1 AN: 15304

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.000193 AC: 1 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4816

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10612

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.000162 AC: 11 AN: 68032

Other (OTH) AF: 0.000473 AC: 1 AN: 2112

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.000453

Asia WGS AF: 0.000866 AC: 3 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, single submitter

Submissions by phenotype

Ichthyosis, hystrix-like, with hearing loss Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Autosomal recessive nonsyndromic hearing loss 1A Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Autosomal dominant nonsyndromic hearing loss 3A Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
CADD	Benign	1.4
DANN	Benign	0.29
PhyloP100		-0.24

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: rs112457424; hg19: chr13-20762617;