rs141423405

Positions:

chr21-34370707-C-T

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 0P and 4B. BS2

The NM_172201.2(KCNE2):c.229C>T(p.Arg77Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000644 in 1,614,034 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000066 ( 0 hom. )

Consequence

KCNE2
NM_172201.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:1O:1

Conservation

PhyloP100: 2.36

Variant links:

Genes affected

KCNE2 (HGNC:6242): (potassium voltage-gated channel subfamily E regulatory subunit 2) Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. This gene encodes a member of the potassium channel, voltage-gated, isk-related subfamily. This member is a small integral membrane subunit that assembles with the KCNH2 gene product, a pore-forming protein, to alter its function. This gene is expressed in heart and muscle and the gene mutations are associated with cardiac arrhythmia. [provided by RefSeq, Jul 2008]

KCNE2 links:

(HGNC:):

links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

BS2

High AC in GnomAd4 at 7 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein
KCNE2	NM_172201.2 linkuse as main transcript	c.229C>T	p.Arg77Trp	missense_variant	2/2	ENST00000290310.4	NP_751951.1
LOC105372791	XR_937683.3 linkuse as main transcript	n.1147G>A		non_coding_transcript_exon_variant	2/2
LOC105372791	XR_007067848.1 linkuse as main transcript	n.1182G>A		non_coding_transcript_exon_variant	2/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNE2	ENST00000290310.4 linkuse as main transcript	c.229C>T	p.Arg77Trp	missense_variant	2/2	1	NM_172201.2	ENSP00000290310	P1
	ENST00000440403.2 linkuse as main transcript	n.582G>A		non_coding_transcript_exon_variant	2/3	3

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152150

Hom.:

Cov.:

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:

0.000103

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000636

AC:

AN:

251440

Hom.:

AF XY:

0.0000736

AC XY:

AN XY:

135902

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000868

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000106

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000664

AC:

AN:

1461884

Hom.:

Cov.:

AF XY:

0.0000578

AC XY:

AN XY:

727244

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000134

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000764

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152150

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74322

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:

0.000103

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000119

Hom.:

Bravo

AF:

0.0000642

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000233

AC:

ExAC

AF:

0.0000741

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000237

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:1Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jun 15, 2018	The R77W variant in the KCNE2 gene has been reported in patients with prolonged QT intervals (Millat et al., 2006; Chevalier et al., 2007) and in a patient with aborted cardiac arrest (Roberts et al., 2017). Initially, Millat et al. (2006) reported R77W in one individual with a prolonged QTc interval of 514 ms, syncope, and bradycardia. Subsequently, Chevalier et al. (2007) reported R77W in one individual with a prolonged QTc interval of >600 ms and atrioventricular block. In addition, this variant has also been identified independently in multiple unrelated individuals referred for LQTS genetic testing at GeneDx; however, thus far, segregation data is limited or absent for these individuals due to the lack of clinical information provided and/or insufficient participation by informative family members. Moreover, functional studies indicate that R77W does not impact potassium channel current (Chevalier et al., 2007). The R77W variant is observed in 19/246246 (0.008%) alleles from individuals of multiple ethnic backgrounds in large population cohorts (Lek et al., 2016). Nonetheless, the R77W variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. Finally, in-silico analyses, including protein predictors and evolutionary conservation, support a deleterious effect. Therefore, based on the currently available information, it is unclear whether this variant is pathogenic or benign. -
Uncertain significance, criteria provided, single submitter	clinical testing	AiLife Diagnostics, AiLife Diagnostics	Jun 14, 2020	- -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Sep 04, 2018

Variant summary: KCNE2 c.229C>T (p.Arg77Trp) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 7.7e-05 in 246246 control chromosomes. The observed variant frequency is approximately 1.1 fold of the estimated maximal expected allele frequency for a pathogenic variant in KCNE2 causing Arrhythmia phenotype (7e-05), suggesting that the variant may be benign. c.229C>T has been reported in the literature in individuals affected with LQTS, Brugada syndrome and sudden death (Chevalier_2007, Di Resta_2015, Methner_2016, Millat_2006), without strong evidence for causality. These report(s) do not provide unequivocal conclusions about association of the variant with Arrhythmia. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. One laboratory classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as a VUS. -

Atrial fibrillation, familial, 4;C3150953:Long QT syndrome 6

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 02, 2021

- -

Long QT syndrome

Uncertain:1

Uncertain significance, no assertion criteria provided

research

CSER _CC_NCGL, University of Washington

Jun 01, 2014

- -

Long QT syndrome 6

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 27, 2022

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 77 of the KCNE2 protein (p.Arg77Trp). This variant is present in population databases (rs141423405, gnomAD 0.01%). This missense change has been observed in individual(s) with or evaluated for long QT syndrome, arrhythmia, or Brugada syndrome (PMID: 16922724, 17275752, 26220970, 28794082). ClinVar contains an entry for this variant (Variation ID: 67614). 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: "Probably Damaging"; Align-GVGD: "Class C15"). Experimental studies have shown that this missense change does not substantially affect KCNE2 function (PMID: 17275752). 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. -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 17, 2022

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

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 as associated with Long QT syndrome in the following publications (PMID:16922724;PMID:17275752;PMID:22378279). This is a literature report, and does not necessarily reflect the clinical interpretation of the Imperial College / Royal Brompton Cardiovascular Genetics laboratory. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.18

BayesDel_addAF

Uncertain

0.057

BayesDel_noAF

Uncertain

0.080

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.79

Eigen

Uncertain

0.30

Eigen_PC

Uncertain

0.25

FATHMM_MKL

Benign

0.46

LIST_S2

Uncertain

0.90

M_CAP

Benign

0.084

MetaRNN

Uncertain

0.63

MetaSVM

Uncertain

0.33

MutationAssessor

Benign

1.9

MutationTaster

Benign

0.88

PrimateAI

Benign

0.23

PROVEAN

Uncertain

-2.5

REVEL

Uncertain

0.56

Sift

Uncertain

0.011

Sift4G

Uncertain

0.024

Polyphen

0.99

Vest4

0.55

MVP

0.95

MPC

0.51

ClinPred

0.50

GERP RS

5.7

Varity_R

0.30

gMVP

0.71

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