rs145438428

Variant names:

• chr13-20223076-C-T
• rs145438428
• NM_001110219.3:c.405G>A

Variant summary

Our verdict is Benign. Variant got -8 ACMG points: 2P and 10B. PM2 BP4_Strong BP6 BP7 BS1

The NM_001110219.3(GJB6):​c.405G>A​(p.Thr135Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000234 in 1,613,688 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00051 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00021 (0 hom.)
• Consequence: GJB6 NM_001110219.3 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:4
• Conservation: PhyloP100: -3.95

Genes affected

GJB6 (HGNC:4288): (gap junction protein beta 6) Gap junctions allow the transport of ions and metabolites between the cytoplasm of adjacent cells. They are formed by two hemichannels, made up of six connexin proteins assembled in groups. Each connexin protein has four transmembrane segments, two extracellular loops, a cytoplasmic loop formed between the two inner transmembrane segments, and the N- and C-terminus both being in the cytoplasm. The specificity of the gap junction is determined by which connexin proteins comprise the hemichannel. In the past, connexin protein names were based on their molecular weight, however the new nomenclature uses sequential numbers based on which form (alpha or beta) of the gap junction is present. This gene encodes one of the connexin proteins. Mutations in this gene have been found in some forms of deafness and in some families with hidrotic ectodermal dysplasia. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Benign. Variant got -8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.85).
• BP6: Variant 13-20223076-C-T is Benign according to our data. Variant chr13-20223076-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 311381.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Likely_benign=3}. Variant chr13-20223076-C-T is described in Lovd as [Likely_benign].
• BP7: Synonymous conserved (PhyloP=-3.95 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000512 (78/152214) while in subpopulation AFR AF= 0.00154 (64/41560). AF 95% confidence interval is 0.00124. There are 0 homozygotes in gnomad4. There are 40 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJB6	NM_001110219.3	c.405G>A	p.Thr135Thr	synonymous_variant	Exon 5 of 5	ENST00000647029.1	NP_001103689.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GJB6	ENST00000647029.1	c.405G>A	p.Thr135Thr	synonymous_variant	Exon 5 of 5		NM_001110219.3	ENSP00000493834.1

Frequencies

GnomAD3 genomes AF: 0.000513 AC: 78 AN: 152096 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00154

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000147

Gnomad OTH AF: 0.000961

GnomAD3 exomes AF: 0.000215 AC: 54 AN: 251416 Hom.: 0 AF XY: 0.000206 AC XY: 28 AN XY: 135880

Gnomad AFR exome AF: 0.00160

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000924

Gnomad NFE exome AF: 0.000220

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000205 AC: 300 AN: 1461474 Hom.: 0 Cov.: 32 AF XY: 0.000198 AC XY: 144 AN XY: 727070

Gnomad4 AFR exome AF: 0.00143

Gnomad4 AMR exome AF: 0.0000447

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.0000936

Gnomad4 NFE exome AF: 0.000210

Gnomad4 OTH exome AF: 0.000166

GnomAD4 genome AF: 0.000512 AC: 78 AN: 152214 Hom.: 0 Cov.: 32 AF XY: 0.000537 AC XY: 40 AN XY: 74432

Gnomad4 AFR AF: 0.00154

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000147

Gnomad4 OTH AF: 0.000951

Alfa AF: 0.000364 Hom.: 0

Bravo AF: 0.000552

EpiCase AF: 0.000109

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:4

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hidrotic ectodermal dysplasia syndrome 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. -

not specified Benign:1

Apr 28, 2017

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Thr135Thr in exon 03 of GJB6: This variant is not expected to have clinical si gnificance because it does not alter an amino acid residue, is not located withi n the splice consensus sequence, and has been identified in 0.2% (38/24034) of A frican chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.bro adinstitute.org; dbSNP rs145438428). -

Hidrotic ectodermal dysplasia syndrome;C2673759:Autosomal recessive nonsyndromic hearing loss 1A;C2675235:Autosomal recessive nonsyndromic hearing loss 1B;C2675237:Autosomal dominant nonsyndromic hearing loss 3B Benign:1

Nov 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

GJB6-related disorder Benign:1

Jul 23, 2019

PreventionGenetics, part of Exact Sciences

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

not provided Benign:1

Jan 26, 2021

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	-0.85
CADD	Benign	0.58
DANN	Benign	0.78

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: rs145438428; hg19: chr13-20797215; COSMIC: COSV53832542; COSMIC: COSV53832542;