rs199473653

Positions:

chr17-70175284-G-A

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong

The NM_000891.3(KCNJ2):c.245G>A(p.Arg82Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,892 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R82W) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.0 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

KCNJ2
NM_000891.3 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5O:1

Conservation

PhyloP100: 10.0

Variant links:

Genes affected

KCNJ2 (HGNC:6263): (potassium inwardly rectifying channel subfamily J member 2) Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein, which has a greater tendency to allow potassium to flow into a cell rather than out of a cell, probably participates in establishing action potential waveform and excitability of neuronal and muscle tissues. Mutations in this gene have been associated with Andersen syndrome, which is characterized by periodic paralysis, cardiac arrhythmias, and dysmorphic features. [provided by RefSeq, Jul 2008]

KCNJ2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 19 ACMG points.

PM1

In a transmembrane_region Helical; Name=M1 (size 24) in uniprot entity KCNJ2_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_000891.3

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr17-70175283-C-T is described in Lovd as [Pathogenic].

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), KCNJ2. . Gene score misZ 2.7459 (greater than the threshold 3.09). Trascript score misZ 3.9347 (greater than threshold 3.09). GenCC has associacion of gene with long QT syndrome, short QT syndrome, Andersen-Tawil syndrome, familial atrial fibrillation, short QT syndrome type 3, catecholaminergic polymorphic ventricular tachycardia.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.99

PP5

Variant 17-70175284-G-A is Pathogenic according to our data. Variant chr17-70175284-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 67569.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-70175284-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNJ2	NM_000891.3 linkuse as main transcript	c.245G>A	p.Arg82Gln	missense_variant	2/2	ENST00000243457.4	NP_000882.1	P63252

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNJ2	ENST00000243457.4 linkuse as main transcript	c.245G>A	p.Arg82Gln	missense_variant	2/2	1	NM_000891.3	ENSP00000243457.2		P63252
KCNJ2	ENST00000535240.1 linkuse as main transcript	c.245G>A	p.Arg82Gln	missense_variant	2/2	1		ENSP00000441848.1		P63252

Frequencies

GnomAD3 genomes

AF:

0.00

AC:

AN:

152206

Hom.:

Cov.:

FAILED QC

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461892

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727248

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:

0.00000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

152206

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74372

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:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Andersen Tawil syndrome;C1865018:Short QT syndrome type 3

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 23, 2022

For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. Experimental studies have shown that this missense change affects KCNJ2 function (PMID: 16217063, 22589293). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 67569). This missense change has been observed in individuals with long QT syndrome and Andersen‚ÄìTawil syndrome (PMID: 16217063, 22589293, 22806368, 23516313, 23644778, 23867365, 24861851, 28003625). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 82 of the KCNJ2 protein (p.Arg82Gln). -

not provided

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jan 26, 2023

Reported in an individual with LQTS and no extra-cardiac findings; inherited from an unaffected mother (Maltese et al., 2017); In vitro studies demonstrate that expression of R82Q alone results in nonfunctional potassium channels whereas co-expresssion of R82Q and the wild-type protein results in a dominant negative effect (Davies et al., 2005); Not observed at significant frequency in large population cohorts (gnomAD); 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: 24383070, 16932562, 17341397, 22806368, 22589293, 28003625, 23644778, 16217063, 24861851, 29606556, 23516313, 31737537, 33623294, Garde2020[noPMID]) -

Andersen Tawil syndrome

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Center For Human Genetics And Laboratory Diagnostics, Dr. Klein, Dr. Rost And Colleagues

Jul 05, 2017

- -

Cardiovascular phenotype

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 11, 2017

The p.R82Q variant (also known as c.245G>A), located in coding exon 1 of the KCNJ2 gene, results from a G to A substitution at nucleotide position 245. The arginine at codon 82 is replaced by glutamine, an amino acid with highly similar properties. This alteration has been reported in an individual with long QT syndrome (Maltese PE et al. Int Heart J, 2017 Feb;58:81-87). This variant has also been described in patients with Andersen-Tawil syndrome (ATS), including those with the cardiovascular phenotype (Davies NP et al. Neurology. 2005;65:1083-9; Kimura H et al. Circ Cardiovasc Genet. 2012;5:344-53; Limberg MM et al. Basic Res Cardiol. 2013;108:353). Functional in vitro analyses have suggested that this variant demonstrates dominant negative effects (Davies et al 2005; Kimura et al 2012). Another alteration involving the same amino acid, p.R82W (c.244C>T), has been reported in patients with ATS (Tester DJ et al. Heart Rhythm. 2006;3:800-5). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Cardiac arrhythmia

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

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

Jun 24, 2024

Variant summary: KCNJ2 c.245G>A (p.Arg82Gln) results in a conservative amino acid change located in the potassium channel, inwardly rectifying, transmembrane domain (IPR040445) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251488 control chromosomes. c.245G>A has been reported in the literature in the heterozygous state individuals affected with autosomal dominant Andersen-Tawil syndrome or Long QT syndrome and was de novo in at least one patient (e.g. Davies_2005, Tan_2012, Maltese_2017, Cornthwaite_2022, Kimura_2012). These data indicate that the variant is likely to be associated with disease. In vitro studies in X. laevis oocytes and CHO cells shows that this variant results in reduced potassium channel conductance compared to wildtype (e.g. Davies_2005, Kimura_2012). The following publications have been ascertained in the context of this evaluation (PMID: 36068917, 16217063, 22589293, 28003625, 22806368). ClinVar contains an entry for this variant (Variation ID: 67569). Based on the evidence outlined above, the variant was classified as pathogenic. -

Congenital long QT syndrome

Other:1

not provided, no classification provided

literature only

Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust

This variant has been reported in the following publications (PMID:16217063). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.52

BayesDel_addAF

Pathogenic

0.56

BayesDel_noAF

Pathogenic

0.56

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.98

D;D

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.98

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

.;D

M_CAP

Pathogenic

0.68

MetaRNN

Pathogenic

0.99

D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.9

H;H

PrimateAI

Pathogenic

0.82

PROVEAN

Uncertain

-3.4

D;D

REVEL

Pathogenic

0.94

Sift

Uncertain

0.0010

D;D

Sift4G

Uncertain

0.0030

D;D

Polyphen

1.0

D;D

Vest4

0.96

MutPred

0.96

Loss of MoRF binding (P = 0.0281);Loss of MoRF binding (P = 0.0281);

MVP

0.99

MPC

2.1

ClinPred

1.0

GERP RS

5.7

Varity_R

0.92

gMVP

0.97

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