rs200343670

Positions:

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM1BS2

The NM_000238.4(KCNH2):c.383A>G(p.Asn128Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000167 in 1,613,958 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. N128T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000016 ( 0 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 7.47

Variant links:

Genes affected

KCNH2 (HGNC:6251): (potassium voltage-gated channel subfamily H member 2) This gene encodes a component of a voltage-activated potassium channel found in cardiac muscle, nerve cells, and microglia. Four copies of this protein interact with one copy of the KCNE2 protein to form a functional potassium channel. Mutations in this gene can cause long QT syndrome type 2 (LQT2). Transcript variants encoding distinct isoforms have been identified. [provided by RefSeq, May 2022]

KCNH2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000238.4

BS2

High AC in GnomAdExome4 at 23 AD,Digenic gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNH2	NM_000238.4 linkuse as main transcript	c.383A>G	p.Asn128Ser	missense_variant	3/15	ENST00000262186.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNH2	ENST00000262186.10 linkuse as main transcript	c.383A>G	p.Asn128Ser	missense_variant	3/15	1	NM_000238.4	P1	Q12809-1
KCNH2	ENST00000532957.5 linkuse as main transcript	n.606A>G		non_coding_transcript_exon_variant	3/9	2
KCNH2	ENST00000684241.1 linkuse as main transcript	n.1216A>G		non_coding_transcript_exon_variant	1/13

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152074

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000725

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:

0.000478

GnomAD3 exomes

AF:

0.00000795

AC:

AN:

251450

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135912

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.0000462

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000157

AC:

AN:

1461884

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

727248

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

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:

0.0000187

Gnomad4 NFE exome

AF:

0.0000180

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152074

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74286

show subpopulations

Gnomad4 AFR

AF:

0.0000725

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:

0.000478

Alfa

AF:

0.0000579

Hom.:

Bravo

AF:

0.0000264

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Long QT syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Sep 17, 2023	This missense variant replaces asparagine with serine at codon 128 of the KCNH2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). Splice site prediction tools suggest that this variant may impact RNA splicing. To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 2/251450 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Jan 24, 2023	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. 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 tolerated. ClinVar contains an entry for this variant (Variation ID: 191473). This variant has not been reported in the literature in individuals affected with KCNH2-related conditions. This variant is present in population databases (rs200343670, gnomAD 0.007%). This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 128 of the KCNH2 protein (p.Asn128Ser). -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

research

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Jun 24, 2013

- -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 28, 2023

The p.N128S variant (also known as c.383A>G), located in coding exon 3 of the KCNH2 gene, results from an A to G substitution at nucleotide position 383. The asparagine at codon 128 is replaced by serine, an amino acid with highly 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. -

Cardiac arrhythmia

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Nov 03, 2022

This missense variant replaces asparagine with serine at codon 128 of the KCNH2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). Splice site prediction tools suggest that this variant may impact RNA splicing. To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 2/251450 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.29

BayesDel_addAF

Benign

-0.032

BayesDel_noAF

Benign

-0.10

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.83

D;D

Eigen

Benign

-0.16

Eigen_PC

Benign

0.042

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.97

D;D

M_CAP

Pathogenic

0.35

MetaRNN

Uncertain

0.68

D;D

MetaSVM

Pathogenic

0.87

MutationAssessor

Benign

0.28

N;.

MutationTaster

Benign

0.99

D;D;D

PrimateAI

Uncertain

0.70

PROVEAN

Uncertain

-3.2

D;.

REVEL

Uncertain

0.49

Sift

Benign

0.069

T;.

Sift4G

Benign

0.23

T;T

Polyphen

0.0020

B;.

Vest4

0.81

MVP

0.84

MPC

0.82

ClinPred

0.39

GERP RS

4.7

Varity_R

0.45

gMVP

0.96

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.11

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