rs80338950

chr13-20189031-C-Gchr13-20189031-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM5 PP3_Strong PP5

The NM_004004.6(GJB2):c.551G>C(p.Arg184Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000316 in 1,613,890 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R184Q) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000032 (0 hom.)
• Consequence: GJB2 NM_004004.6 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:15 U:1 O:1
• Conservation: PhyloP100: 7.86

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_004004.6
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-20189031-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 29662.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.974
• PP5: Variant 13-20189031-C-G is Pathogenic according to our data. Variant chr13-20189031-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 17007.We mark this variant Likely_pathogenic, oryginal submissions are: {not_provided=1, Pathogenic=11, Uncertain_significance=1}. Variant chr13-20189031-C-G is described in Lovd as [Likely_pathogenic]. Variant chr13-20189031-C-G is described in Lovd as [Pathogenic]. Variant chr13-20189031-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GJB2	NM_004004.6	c.551G>C	p.Arg184Pro	missense_variant	2/2	ENST00000382848.5
GJB2	XM_011535049.3	c.551G>C	p.Arg184Pro	missense_variant	2/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GJB2	ENST00000382848.5	c.551G>C	p.Arg184Pro	missense_variant	2/2	1	NM_004004.6	P1
GJB2	ENST00000382844.2	c.551G>C	p.Arg184Pro	missense_variant	1/1			P1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152120 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: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000588

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000597 AC: 15 AN: 251296 Hom.: 0 AF XY: 0.0000663 AC XY: 9 AN XY: 135832

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000116

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000653

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000528

Gnomad OTH exome AF: 0.000489

GnomAD4 exome AF: 0.0000322 AC: 47 AN: 1461770 Hom.: 0 Cov.: 32 AF XY: 0.0000330 AC XY: 24 AN XY: 727170

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000894

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000315

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152120 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74314

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000588

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000526 Hom.: 0

Bravo AF: 0.0000453

ExAC AF: 0.0000412 AC: 5

EpiCase AF: 0.000164

EpiControl AF: 0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:15 Uncertain:1 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Autosomal recessive nonsyndromic hearing loss 1A Pathogenic:6 Uncertain:1 Other:1

not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Feb 01, 2004	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Mar 23, 2016	Variant summary: Variant affects a conserved nucleotide and results in a replacement of a large size and basic Arginine (R) with a medium size and hydrophobic Proline (P). 5/5 in silico tools predict the variant to be disease causing. The variant was observed in the large and broad cohorts of the ExAC project at an allele frequency of 0.00412% which does not exceed the maximal expected allele frequency of a disease causing GJB2 allele (2.5%). The variant was reported in several patients affected with hearing loss, most of them were homozygous for the variant of interest or compound heterozygotes with another pathogenic GJB2 mutation indicating pathogenicity. A functional study demonstrated R184P as a coupling deficient variant. In experiments with oligomerization of mutated connexin proteins R184P was detected only as monomeric protein, suggesting inability to form hemichannels further supporting pathogenicity. Additionally, several clinical diagnostic laboratories and reputable database classify variant as pathogenic (without evidence to independently evaluate). Furthermore, variants affecting the same codon, p.R184W, p.R184G and p.R184Q were reported to be associated with Deafness, autosomal recessive 1 and Deafness, autosomal dominant 3, respectively indicating the variant to be located in a mutational hotspot and the Arg184 residue to be functionally important. Considering all evidence, the variant was classified as a Pathogenic. -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Aug 12, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Oct 18, 2018	Across a selection of the available literature, GJB2 the c.551G>C (p.Arg184Pro) missense variant has been identified in a sixteen individuals affected with hearing loss including three homozygotes, ten compound heterozygotes, and three heterozygotes (Murgia et al. 1999; Azaiez et al. 2004; Tang et al. 2006; Mani et al. 2009; Dodson et al. 2011; Keivani et al. 2015). The variant was also identified in six unaffected heterozygotes (Keivani et al. 2015). The p.Arg184Pro variant was absent from 355 controls but is reported at a frequency of 0.000087 in the Latino population of the Genome Aggregation Database. In vitro functional studies in HeLa cells showed that the p.Arg184Pro variant resulted in defective trafficking, exhibited increased RNA expression versus wild type and resulted in a coupling defect (Mani et al. 2009; Thönnissen et al. 2002). In Xenopus oocytes the variant protein was unable to induce formation of intracellular channels thus resulting in a loss of function (Bruzzone et al. 2003). Based on the collective evidence, the p.Arg184Pro variant is classified as pathogenic for autosomal recessive nonsyndromic hearing loss. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -
Pathogenic, no assertion criteria provided	clinical testing	Counsyl	Sep 09, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genomic Diagnostic Laboratory, Division of Genomic Diagnostics, Children's Hospital of Philadelphia	May 09, 2017	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center	Apr 04, 2024	- -

not provided Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Feb 07, 2022	Published functional studies demonstrate a damaging effect; variant results in the failure of intracellular coupling and gap junction channel formation (Thnnissen et al., 2002; Bruzzone et al., 2003); A different missense change at this residue (p.(R184W) has been reported as pathogenic in the published literature and at GeneDxin association with autosomal recessive GJB2-related hearing loss (Wilcox et al., 2000); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 24529908, 15967879, 17485979, 12176179, 11551103, 22808909, 15666300, 9336442, 15855033, 12417772, 19173109, 15365987, 19715472, 19941053, 18560174, 19371219, 19125024, 14985372, 26381000, 17935238, 16380907, 21465647, 18941476, 12505163, 22975760, 10544226, 25388846, 26117665, 25085637, 17666888, 31980526, 32300592, 12176036, 34426522, 33096615, 31589614, 32067424, 10874298, 12189493, 25708704, 17041943, 27535533, 24158611, 10982180, 10830906) -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 16, 2024	This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 184 of the GJB2 protein (p.Arg184Pro). This variant is present in population databases (rs80338950, gnomAD 0.009%). This missense change has been observed in individuals with autosomal recessive nonsyndromic deafness (PMID: 10874298, 18941476, 19371219, 25708704, 26117665). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 17007). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GJB2 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects GJB2 function (PMID: 12176036, 12189493, 12505163, 15241677, 18941476). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Jul 23, 2020	The frequency of this variant in the general population is consistent with pathogenicity. Found in at least one patient with expected phenotype for this gene. Predicted to have a damaging effect on the protein. Other pathogenic or likely pathogenic variants affect the same amino acid. In multiple individuals, this variant has been seen with a single recessive pathogenic variant in the same gene, suggesting this variant may also be pathogenic. Assessment of experimental evidence suggests this variant results in abnormal protein function. Strong co-segregation with disease, and data include affected and unaffected individuals from multiple families. -
Pathogenic, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Nov 25, 2020	The GJB2 c.551G>C; p.Arg184Pro variant (rs80338950) has been described in a homozygous or compound heterozygous state in several individuals and families with nonsyndomic hearing loss (Denoyelle 1997, Dodson 2011, Keivani 2015). In addition, functional assays suggest that this variant impairs membrane trafficking, intercellular coupling, and hemichannel formation (Bruzzone 2003, Mani 2009, Thonnissen 2002). This variant is reported as pathogenic in ClinVar (Variation ID: 17007), and is observed in the general population at a low allele frequency of 0.006% (17/282684 alleles) in the Genome Aggregation Database. The arginine at codon 184 is highly conserved, and computational algorithms (SIFT, PolyPhen2) predict this variant to be damaging to the protein. Additionally, other amino acid substitutions at this codon (Gln, Gly, Trp) have been reported in individuals with hearing loss and are considered disease-causing (Pang 2014, Wang 2000, Zoll 2003). Based on the above information, p.Arg184Pro is considered pathogenic for autosomal recessive hearing loss. References: Bruzzone R et al. Loss-of-function and residual channel activity of connexin26 mutations associated with non-syndromic deafness. FEBS Lett. 2003 Jan 2;533(1-3):79-88. Denoyelle F et al. Prelingual deafness: high prevalence of a 30delG mutation in the connexin 26 gene. Hum Mol Genet. 1997 Nov;6(12):2173-7. Dodson KM et al. Vestibular dysfunction in DFNB1 deafness. Am J Med Genet A. 2011 May;155A(5):993-1000. Keivani A et al. A new compound heterozygous mutation in GJB2 causes nonsyndromic hearing loss in a consanguineous Iranian family. Int J Pediatr Otorhinolaryngol. 2015 Apr;79(4):553-6. Mani RS et al. Functional consequences of novel connexin 26 mutations associated with hereditary hearing loss. Eur J Hum Genet. 2009 Apr;17(4):502-9. Pang X et al. Characterization of spectrum, de novo rate and genotype-phenotype correlation of dominant GJB2 mutations in Chinese hans. PLoS One. 2014 Jun 19;9(6):e100483. Thonnissen E et al. Human connexin26 (GJB2) deafness mutations affect the function of gap junction channels at different levels of protein expression. Hum Genet. 2002 Aug;111(2):190-7. Wilcox SA et al. High frequency hearing loss correlated with mutations in the GJB2 gene. Hum Genet. 2000 Apr;106(4):399-405. Zoll B et al. Evaluation of Cx26/GJB2 in German hearing impaired persons: mutation spectrum and detection of disequilibrium between M34T (c.101T>C) and -493del10. Hum Mutat. 2003 Jan;21(1):98. -

Hearing loss Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Clinical Molecular Genetics Laboratory, Johns Hopkins All Children's Hospital

Jun 01, 2015

- -

Nonsyndromic genetic hearing loss Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

INGEBI, INGEBI / CONICET

Aug 31, 2020

Based on ACMG/AMP guidelines and Hearing Loss Expert Panel specific criteria: the filter allele frequency of c.551G>C, p.Arg184Pro variant in GJB2 gene is 0,0038% (4/35426 Latino alleles with 95% CI) from Genome Aggregation Database (http://gnomad.broadinstitute.org; calculated by using inverse allele frequency at https://www.cardiodb.org/allelefrequencyapp/), which meets the PM2 criteria. This variant was identified at least in five individuals in trans with several known pathogenic variants (PM3_VeryStrong; PMID: 24158611, 10874298, 10982180, 11551103, 12176179, 16380907, 16380907, 17485979). Computational evidence predicted a damage impact of the mutation to the protein meeting PP3 rule (REVELscore: 0,983) Functional studies demonstrated that: mutant protein is neither trafficked to membrane nor able to oligomerize efficiently and unable to form functional GJCh in HeLa cells (PMID: 12176036, 1218943). Moreover, p.Arg184Pro mutant did not induce the formation of homotypic junctional channels, since the levels of conductance measured never exceeded background values in Xenopus laevis oocytes (PMID: 12505163), PS3_Moderate Therefore, this variant meets criteria to be classified as pathogenic for autosomal recessive non-syndromic hearing loss (PM2, PM3_VeryStrong, PP3 and PS3_Moderate). -

Autosomal dominant keratitis-ichthyosis-hearing loss syndrome;C0265964:Mutilating keratoderma;C0266004:Knuckle pads, deafness AND leukonychia syndrome;C1835672:Palmoplantar keratoderma-deafness syndrome;C1844678:X-linked mixed hearing loss with perilymphatic gusher;C1865234:Ichthyosis, hystrix-like, with hearing loss;C2673759:Autosomal recessive nonsyndromic hearing loss 1A;C2675750:Autosomal dominant nonsyndromic hearing loss 3A Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Autosomal dominant nonsyndromic hearing loss 3A Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Jan 26, 2019

This variant was classified as: Pathogenic. The following ACMG criteria were applied in classifying this variant: PM2,PP2,PP3,PP5. -

Rare genetic deafness Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Aug 26, 2022

The p.Arg184Pro variant in GJB2 has been identified in the homozygous or compound heterozygous state in more than 50 individuals with hearing loss, and in vitro functional studies provide some evidence that this variant may impact protein function (Thonnissen 2002 PMID: 12189493, Bruzzone 2003 PMID: 12505163, Mani 2009 PMID: 18941476). This variant has been identified in 1/11568 of Latino chromosomes, 1/16592 of South Asian chromosomes, and 3/67458 of European chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs80338950). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. In summary, the p.Arg184Pro variant meets our criteria to be classified as pathogenic for autosomal recessive hearing loss based upon strong association with the disease, low frequency in the general population, and supportive functional evidence. ACMG/AMP criteria applied: PM3_VeryStrong, PM2_Supporting, PP3, PS3_Supporting. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D;D;D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Pathogenic	0.56	D
MetaRNN	Pathogenic	0.97	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.1	H;H;H
MutationTaster	Benign	1.0	A;A
PrimateAI	Uncertain	0.75	T
PROVEAN	Pathogenic	-6.1	D;D;.
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0	D;D;.
Polyphen		1.0	D;D;D
Vest4		0.99
MVP		0.97
MPC		0.32
ClinPred		0.99	D
GERP RS		5.7
Varity_R		0.99
gMVP		0.99

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

Publications

LitVar

Other links and lift over

dbSNP: rs80338950; hg19: chr13-20763170;