NM_000238.4:c.3322C>G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 1P and 5B. PP2BP4BS2

The NM_000238.4(KCNH2):c.3322C>G(p.Leu1108Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00003 in 1,598,314 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000032 ( 2 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:1O:1

Conservation

PhyloP100: 2.76

Publications

3 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: Likely_benign. The variant received -4 ACMG points.

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.

BP4

Computational evidence support a benign effect (MetaRNN=0.2836648).

BS2

High AC in GnomAdExome4 at 46 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4 link	c.3322C>G	p.Leu1108Val	missense_variant	Exon 14 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.3322C>G	p.Leu1108Val	missense_variant	Exon 14 of 15	1	NM_000238.4	ENSP00000262186.5		Q12809-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152124

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:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000578

AC:

AN:

242114

AF XY:

0.0000919

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000170

GnomAD4 exome

AF:

0.0000318

AC:

AN:

1446190

Hom.:

Cov.:

AF XY:

0.0000474

AC XY:

AN XY:

716900

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33222

American (AMR)

AF:

0.00

AC:

AN:

43782

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25428

East Asian (EAS)

AF:

0.00

AC:

AN:

39304

South Asian (SAS)

AF:

0.000508

AC:

AN:

84716

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52748

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5696

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1101604

Other (OTH)

AF:

0.0000503

AC:

AN:

59690

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.482

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

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:

0.0000131

AC:

AN:

152124

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74312

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41420

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5170

South Asian (SAS)

AF:

0.000414

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

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:

0.00

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000824

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:1Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Long QT syndrome 2

Uncertain:2

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Neuberg Centre For Genomic Medicine, NCGM

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The missense c.3322C>Gp.Leu1108Val variant in KCNH2 gene has been reported previously in individuals affected with long QT syndrome Koo SH, et al., 2006. The p.Leu1108Val variant has been reported with allele frequency of 0.006% in gnomAD Exomes and is novel not in any individuals in 1000 Genomes. This variant has been reported to the ClinVar database as Likely Benign / Uncertain Significance multiple submissions. The amino acid change p.Leu1108Val in KCNH2 is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. The amino acid Leu at position 1108 is changed to a Val changing protein sequence and it might alter its composition and physico-chemical properties. For these reasons, this variant has been classified as a Variant of Uncertain Significance VUS. -

Long QT syndrome

Uncertain:1

Jan 17, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 1108 of the KCNH2 protein (p.Leu1108Val). This variant is present in population databases (rs199473031, gnomAD 0.05%), and has an allele count higher than expected for a pathogenic variant. This variant has not been reported in the literature in individuals affected with KCNH2-related conditions. ClinVar contains an entry for this variant (Variation ID: 67488). 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. 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

Uncertain:1

Sep 20, 2021

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.3322C>G (p.L1108V) alteration is located in exon 14 (coding exon 14) of the KCNH2 gene. This alteration results from a C to G substitution at nucleotide position 3322, causing the leucine (L) at amino acid position 1108 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Cardiac arrhythmia

Benign:1

Oct 18, 2019

Color Diagnostics, LLC DBA Color Health

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

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 in the following publications (PMID:16487223). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.073

CardioboostArm

Benign

0.00047

BayesDel_addAF

Benign

-0.0013

BayesDel_noAF

Uncertain

0.090

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.40

.;T

Eigen

Uncertain

0.23

Eigen_PC

Uncertain

0.29

FATHMM_MKL

Uncertain

0.87

LIST_S2

Uncertain

0.86

D;D

M_CAP

Pathogenic

0.76

MetaRNN

Benign

0.28

T;T

MetaSVM

Pathogenic

0.90

MutationAssessor

Benign

1.1

.;L

PhyloP100

2.8

PrimateAI

Benign

0.48

PROVEAN

Benign

-0.77

N;N

REVEL

Uncertain

0.44

Sift

Benign

0.43

T;T

Sift4G

Benign

0.58

T;T

Polyphen

0.96

D;P

Vest4

0.34

MutPred

0.14

.;Gain of loop (P = 0.1069);

MVP

0.80

MPC

0.19

ClinPred

0.14

GERP RS

4.9

Varity_R

0.21

gMVP

0.39

Mutation Taster

=49/51

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