rs199472901

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM1PP2BS2_Supporting

The NM_000238.4(KCNH2):c.1307C>T(p.Thr436Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000254 in 1,614,072 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. T436T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000024 ( 0 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5O:1

Conservation

PhyloP100: 1.23

Publications

14 publications found

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 Gene-Disease associations (from GenCC):

long QT syndrome
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
long QT syndrome 2
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
short QT syndrome
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
short QT syndrome type 1
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
Brugada syndrome
Inheritance: AD Classification: MODERATE, NO_KNOWN Submitted by: ClinGen, Genomics England PanelApp

KCNH2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000238.4

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 158 curated pathogenic missense variants (we use a threshold of 10). The gene has 38 curated benign missense variants. Gene score misZ: 3.3724 (above the threshold of 3.09). Trascript score misZ: 2.4846 (below the threshold of 3.09). GenCC associations: The gene is linked to long QT syndrome 2, Brugada syndrome, short QT syndrome type 1, short QT syndrome, long QT syndrome.

BS2

High AC in GnomAd4 at 6 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4 link	c.1307C>T	p.Thr436Met	missense_variant	Exon 6 of 15	ENST00000262186.10	NP_000229.1	Q12809-1Q15BH2A0A090N8Q0

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10 link	c.1307C>T	p.Thr436Met	missense_variant	Exon 6 of 15	1	NM_000238.4	ENSP00000262186.5		Q12809-1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152188

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:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.0000239

AC:

AN:

251460

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000239

AC:

AN:

1461884

Hom.:

Cov.:

AF XY:

0.0000303

AC XY:

AN XY:

727242

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.0000187

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000234

AC:

AN:

1112010

Other (OTH)

AF:

0.0000497

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.488

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152188

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74330

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41440

American (AMR)

AF:

0.00

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000193

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68038

Other (OTH)

AF:

0.000478

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000666

Hom.:

Bravo

AF:

0.0000302

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Long QT syndrome

Uncertain:2

Sep 23, 2024

All of Us Research Program, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces threonine with methionine at codon 436 of the KCNH2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). Functional studies have been inconsistent regarding the ability of this variant to impair KCNH2 protein function (PMID: 16432067, 23303164, 26129877, 34002542). This variant has been identified in at least two individuals affected with long QT syndrome and reported to be de novo in one of them (PMID: 9927399, 10973849, ClinVar SCV000752717.3). This variant has also been reported in individuals affected with atrial fibrillation (PMID: 26129877), epilepsy (PMID: 31696929, 34002542), and dilated cardiomyopathy (PMID: 37904629). This variant has been identified in 9/282850 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Although there is a suspicion for a pathogenic role, 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. -

Dec 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 436 of the KCNH2 protein (p.Thr436Met). This variant is present in population databases (rs199472901, gnomAD 0.01%). This missense change has been observed in individuals with long QT syndrome (PMID: 9927399; internal data). ClinVar contains an entry for this variant (Variation ID: 67184). 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 tolerated. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on KCNH2 function (PMID: 16432067, 23303164, 26129877, 34002542). 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. -

not provided

Uncertain:1

Aug 26, 2020

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Reported in association with LQTS and atrial fibrillation (Priori et al., 1999; Hayashi et al., 2015); Reported in ClinVar as a variant of uncertain significance (ClinVar Variant ID# 67184; Landrum et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Functional studies to date have not yielded consistent conclusions about the effect of this variant on protein function (Anderson et al., 2006; Jou et al., 2013; Hayashi et al., 2015); This variant is associated with the following publications: (PMID: 16432067, 9927399, 26129877, 23303164, 11854117, 10973849) -

Cardiovascular phenotype

Uncertain:1

Feb 15, 2022

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.1307C>T (p.T436M) alteration is located in exon 6 (coding exon 6) of the KCNH2 gene. This alteration results from a C to T substitution at nucleotide position 1307, causing the threonine (T) at amino acid position 436 to be replaced by a methionine (M). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Cardiac arrhythmia

Uncertain:1

Jun 13, 2024

Color Diagnostics, LLC DBA Color Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Congenital long QT syndrome

Other:1

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

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

This variant has been reported as associated with Long QT syndrome in the following publications (PMID:9927399;PMID:11854117;PMID:16432067). 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

0.091

CardioboostArm

Benign

0.0068

BayesDel_addAF

Pathogenic

0.19

BayesDel_noAF

Pathogenic

0.20

CADD

Benign

(source)

DANN

Benign

0.97

DEOGEN2

Uncertain

0.63

.;D;D

Eigen

Benign

-0.65

Eigen_PC

Benign

-0.57

FATHMM_MKL

Benign

0.13

LIST_S2

Benign

0.69

T;T;T

M_CAP

Pathogenic

0.40

MetaRNN

Uncertain

0.55

D;D;D

MetaSVM

Benign

-0.30

MutationAssessor

Benign

0.0

.;N;.

PhyloP100

1.2

PrimateAI

Uncertain

0.61

PROVEAN

Benign

-0.46

N;N;.

REVEL

Uncertain

0.56

Sift

Benign

0.15

T;T;.

Sift4G

Benign

0.11

T;T;T

Polyphen

0.0080

B;B;.

Vest4

0.46

MutPred

0.76

.;Loss of glycosylation at T436 (P = 0.0445);.;

MVP

1.0

MPC

1.2

ClinPred

0.063

GERP RS

2.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.057

gMVP

0.60

Mutation Taster

=16/84

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over