13-20192771-C-T

Variant names:

• chr13-20192771-C-T
• rs397516866
• NM_004004.6:c.-23+12G>A

Variant summary

Our verdict is Benign. The variant received -17 ACMG points: 0P and 17B. BP4_Strong BP6_Very_Strong BS1 BS2_Supporting

The NM_004004.6(GJB2):​c.-23+12G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00543 in 152,182 control chromosomes in the GnomAD database, including 10 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0054 (10 hom., cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: GJB2 NM_004004.6 intron
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:4
• Conservation: PhyloP100: -2.25
• Publications: 1 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: Benign. The variant received -17 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.76).
• BP6: Variant 13-20192771-C-T is Benign according to our data. Variant chr13-20192771-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 44718.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00543 (827/152182) while in subpopulation AFR AF = 0.0189 (784/41550). AF 95% confidence interval is 0.0178. There are 10 homozygotes in GnomAd4. There are 413 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.
• BS2: High Homozygotes in GnomAd4 at 10 AR,AD geneVariant has number of homozygotes lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJB2	NM_004004.6	c.-23+12G>A		intron_variant	Intron 1 of 1	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.-833G>A		5_prime_UTR_variant	Exon 1 of 2		XP_011533351.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GJB2	ENST00000382848.5	c.-23+12G>A		intron_variant	Intron 1 of 1	1	NM_004004.6	ENSP00000372299.4
ENSG00000296095	ENST00000736390.1	n.231+1684G>A		intron_variant	Intron 1 of 3

Frequencies

GnomAD3 genomes AF: 0.00542 AC: 824 AN: 152076 Hom.: 10 Cov.: 33

Gnomad AFR AF: 0.0188

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00229

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: 0.00

Gnomad OTH AF: 0.00382

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 792 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 468

African (AFR) AF: 0.00 AC: 0 AN: 2

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: 14

South Asian (SAS) AF: 0.00 AC: 0 AN: 426

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

Middle Eastern (MID) AC: 0 AN: 0

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 304

Other (OTH) AF: 0.00 AC: 0 AN: 22

GnomAD4 genome AF: 0.00543 AC: 827 AN: 152182 Hom.: 10 Cov.: 33 AF XY: 0.00555 AC XY: 413 AN XY: 74406

African (AFR) AF: 0.0189 AC: 784 AN: 41550

American (AMR) AF: 0.00229 AC: 35 AN: 15294

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5160

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10588

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67972

Other (OTH) AF: 0.00378 AC: 8 AN: 2116

Alfa AF: 0.000768 Hom.: 0

Bravo AF: 0.00602

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:3

Dec 05, 2017

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: The GJB2 c.-23+12G>A variant involves the alteration of a non-conserved nucleotide in the first intron of the gene. One in silico tool predicts a benign outcome for this variant and 4/5 splice prediction tools predict no significant impact on normal splicing. ESE finder predicts that this variant may affect ESE sites at the locus. However, these predictions have yet to be confirmed by functional studies. This variant was found in 167/30820 control chromosomes (2 homozygotes), predominantly observed in the African subpopulation at a frequency of 0.018983 (165/8692). This frequency is about 56 times the estimated maximal expected allele frequency of a dominant pathogenic GJB2 variant (0.0003376), suggesting this is likely a benign polymorphism found primarily in the populations of African origin. In a recessive inheritance model, this frequency does not exceed the maximal expected frequency for a recessive pathogenic GJB2 variant (0.02598). However, the presence of two normal homozygous individuals in the gnomAD database support a benign impact of this variant in either inheritance model. The variant has been found in at least 7 hearing loss patients. However, in 6 reported patients, this variant was found in heterozygous state, suggesting that this variant might not explain the phenotype in the patients because hearing loss is predominantly a recessive disorder, and the high allele frequency in African controls suggests that this variant is not a dominant hearing loss causative variant. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as likely benign or benign. Taken together, this variant is classified as benign. -

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PreventionGenetics, part of Exact Sciences

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 27, 2017

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

c.-23+12G>A in intron 1 of GJB2: This variant is not expected to have clinical s ignificance because it has been identified in 1.9% (165/8692) of African chromos omes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.or g; dbSNP rs397516866). -

not provided Benign:1

Nov 06, 2018

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.76
CADD	Benign	6.6
DANN	Benign	0.97
PhyloP100		-2.3
PromoterAI		-0.024	Neutral
Mutation Taster		=100/0	polymorphism

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: rs397516866; hg19: chr13-20766910;