rs778135438

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PP3_Moderate

The NM_000238.4(KCNH2):c.2053C>T(p.Arg685Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,614,116 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 14/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R685H) has been classified as Uncertain significance.

Frequency

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

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:3

Conservation

PhyloP100: 9.95

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 Uncertain_significance. Variant got 4 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_000238.4

PP3

MetaRNN computational evidence supports a deleterious effect, 0.918

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNH2	NM_000238.4 linkuse as main transcript	c.2053C>T	p.Arg685Cys	missense_variant	8/15	ENST00000262186.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNH2	ENST00000262186.10 linkuse as main transcript	c.2053C>T	p.Arg685Cys	missense_variant	8/15	1	NM_000238.4	P1	Q12809-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152250

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000964

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

GnomAD3 exomes

AF:

0.00000796

AC:

AN:

251316

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135864

show subpopulations

Gnomad AFR exome

AF:

0.0000616

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:

0.00

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461866

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727234

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:

8.99e-7

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152250

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74384

show subpopulations

Gnomad4 AFR

AF:

0.0000964

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

Alfa

AF:

0.0000329

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:3

Revision: criteria provided, conflicting classifications

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	Aug 28, 2023	This missense variant replaces arginine with cysteine at codon 685 of the KCNH2 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with KCNH2-related disorders in the literature. This variant has not been identified 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	Mar 09, 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. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 448974). This variant has not been reported in the literature in individuals affected with KCNH2-related conditions. 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 sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 685 of the KCNH2 protein (p.Arg685Cys). -

Long QT syndrome 2

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

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

May 24, 2017

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Nov 25, 2019

The KCNH2 c.2053C>T; p.Arg685Cys variant (rs778135438), to our knowledge, is not reported in the medical literature but is reported in ClinVar (Variation ID: 448974). This variant is only observed on three alleles in the Genome Aggregation Database, indicating it is not a common polymorphism. The arginine at codon 685 is highly conserved, and computational analyses (SIFT, PolyPhen-2) predict that this variant is deleterious. Additionally, another variant at this codon (c.2054G>A; p.Arg685His) has been reported in individuals with long QT syndrome (Mullally 2013). However, due to limited information, the clinical significance of the p.Arg685Cys variant is uncertain at this time. References: Mullally J et al. Risk of life-threatening cardiac events among patients with long QT syndrome and multiple mutations. Heart Rhythm. 2013 Mar;10(3):378-82. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.96

CardioboostArm

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.41

BayesDel_noAF

Pathogenic

0.53

Cadd

Pathogenic

Dann

Pathogenic

1.0

Eigen

Pathogenic

0.84

Eigen_PC

Pathogenic

0.75

FATHMM_MKL

Uncertain

0.94

LIST_S2

Pathogenic

0.98

D;D;D

M_CAP

Pathogenic

0.82

MetaRNN

Pathogenic

0.92

D;D;D

MetaSVM

Pathogenic

1.1

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Pathogenic

0.91

PROVEAN

Pathogenic

-7.8

D;D;.

REVEL

Pathogenic

0.91

Sift

Pathogenic

0.0

D;D;.

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

D;D;.

Vest4

0.95

MutPred

0.62

.;Loss of MoRF binding (P = 0.001);.;

MVP

0.97

MPC

2.5

ClinPred

1.0

GERP RS

4.4

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.86

gMVP

0.94

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.080

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