rs756258267

Positions:

chrX-71224518-G-A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM1BP4BS2

The NM_000166.6(GJB1):c.811G>A(p.Ala271Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0000461 in 1,193,071 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 15 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A271S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000018 ( 0 hom., 0 hem., cov: 22)

Exomes 𝑓: 0.000049 ( 0 hom. 15 hem. )

Consequence

GJB1
NM_000166.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 4.28

Variant links:

Genes affected

GJB1 (HGNC:4283): (gap junction protein beta 1) This gene encodes a member of the gap junction protein family. The gap junction proteins are membrane-spanning proteins that assemble to form gap junction channels that facilitate the transfer of ions and small molecules between cells. 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 cause X-linked Charcot-Marie-Tooth disease, an inherited peripheral neuropathy. Alternatively spliced transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Oct 2008]

GJB1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

PM1

In a chain Gap junction beta-1 protein (size 282) in uniprot entity CXB1_HUMAN there are 171 pathogenic changes around while only 10 benign (94%) in NM_000166.6

BP4

Computational evidence support a benign effect (MetaRNN=0.27343324).

BS2

High Hemizygotes in GnomAdExome4 at 15 XL gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
GJB1	NM_000166.6 linkuse as main transcript	c.811G>A	p.Ala271Thr	missense_variant	2/2	ENST00000361726.7
GJB1	NM_001097642.3 linkuse as main transcript	c.811G>A	p.Ala271Thr	missense_variant	2/2
GJB1	XM_011530907.3 linkuse as main transcript	c.811G>A	p.Ala271Thr	missense_variant	2/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GJB1	ENST00000361726.7 linkuse as main transcript	c.811G>A	p.Ala271Thr	missense_variant	2/2	1	NM_000166.6	P1

Frequencies

GnomAD3 genomes

AF:

0.0000179

AC:

AN:

111701

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

33867

show subpopulations

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:

0.0000377

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000136

AC:

AN:

146739

Hom.:

AF XY:

0.00

AC XY:

AN XY:

45605

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000161

Gnomad OTH exome

AF:

0.000262

GnomAD4 exome

AF:

0.0000490

AC:

AN:

1081370

Hom.:

Cov.:

AF XY:

0.0000427

AC XY:

AN XY:

351266

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000612

Gnomad4 OTH exome

AF:

0.0000440

GnomAD4 genome

AF:

0.0000179

AC:

AN:

111701

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

33867

show subpopulations

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:

0.0000377

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000434

Hom.:

Bravo

AF:

0.0000302

ExAC

AF:

0.00000837

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Charcot-Marie-Tooth disease

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Oct 28, 2019

- -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 26, 2020

The p.A271T variant (also known as c.811G>A), located in coding exon 1 of the GJB1 gene, results from a G to A substitution at nucleotide position 811. The alanine at codon 271 is replaced by threonine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Charcot-Marie-Tooth Neuropathy X

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 06, 2022

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 271 of the GJB1 protein (p.Ala271Thr). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with GJB1-related conditions. ClinVar contains an entry for this variant (Variation ID: 567218). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.067

BayesDel_addAF

Uncertain

0.14

BayesDel_noAF

Uncertain

-0.040

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Benign

0.20

T;T;T;T;T

FATHMM_MKL

Uncertain

0.95

LIST_S2

Benign

0.75

.;.;.;.;T

M_CAP

Pathogenic

0.85

MetaRNN

Benign

0.27

T;T;T;T;T

MetaSVM

Uncertain

0.48

MutationAssessor

Benign

0.0

N;N;N;N;N

MutationTaster

Benign

0.98

D;D;D

PrimateAI

Uncertain

0.59

PROVEAN

Benign

-0.19

N;.;N;.;N

REVEL

Uncertain

0.36

Sift

Benign

0.12

T;.;T;.;T

Sift4G

Benign

0.11

T;.;T;.;T

Polyphen

0.80

P;P;P;P;P

Vest4

0.17

MutPred

0.21

Gain of relative solvent accessibility (P = 0.0215);Gain of relative solvent accessibility (P = 0.0215);Gain of relative solvent accessibility (P = 0.0215);Gain of relative solvent accessibility (P = 0.0215);Gain of relative solvent accessibility (P = 0.0215);

MVP

0.89

MPC

1.2

ClinPred

0.21

GERP RS

4.2

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.18

gMVP

0.44

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over