7-150951643-C-T

Variant names:

• chr7-150951643-C-T
• rs199473428
• NM_000238.4:c.1750G>A

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM1 PP3_Strong PP5_Very_Strong

The NM_000238.4(KCNH2):​c.1750G>A​(p.Gly584Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000103 in 1,461,876 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:14 O:1
• Conservation: PhyloP100: 7.72

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]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PM1: In a topological_domain Extracellular (size 42) in uniprot entity KCNH2_HUMAN there are 29 pathogenic changes around while only 0 benign (100%) in NM_000238.4
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.959
• PP5: Variant 7-150951643-C-T is Pathogenic according to our data. Variant chr7-150951643-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 67261.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr7-150951643-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.1750G>A	p.Gly584Ser	missense_variant	Exon 7 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.1750G>A	p.Gly584Ser	missense_variant	Exon 7 of 15	1	NM_000238.4	ENSP00000262186.5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251412 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135908

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1461876 Hom.: 0 Cov.: 34 AF XY: 0.0000138 AC XY: 10 AN XY: 727240

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000126

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

Alfa AF: 0.0000363 Hom.: 0

Bravo AF: 0.00000378

TwinsUK AF: 0.00 AC: 0

ALSPAC AF: 0.000259 AC: 1

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:14 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome 2 Pathogenic:4

Sep 29, 2014

Blueprint Genetics

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jun 21, 2023

Institute of Human Genetics Munich, Klinikum Rechts Der Isar, TU München

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Genomics England Pilot Project, Genomics England

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 11, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:3

Jun 01, 2021

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 30, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Published functional studies using patch clamp assays in transfected Chinese hamster ovary (CHO) cells and Xenopus oocytes suggest that the G584S mutant channel causes a loss of the rapid delayed rectifier current due to trafficking and gating defects (Zhao et al., 2009; Perry et al., 2016); Reported as a pathogenic/likely pathogenic variant in ClinVar (ClinVar Variant ID#67261; ClinVar); This variant is associated with the following publications: (PMID: 21440677, 27807201, 24606995, 22581653, 31447099, 15176425, 20659946, 20566482, 22949429, 25417810, 25649125, 26187847, 26669661, 19490267, 26958806, 19716085, 10862094, 23098067, 15840476, 10973849, 10483966, 19841300, 31358886, 28431243, 32048431, 34319147, 33087929) -

Aug 17, 2019

Mayo Clinic Laboratories, Mayo Clinic

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PS3_Supporting, PS-Moderate, PP2, PP3, PP1_Moderate, PM1 -

Congenital long QT syndrome Pathogenic:1 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:10483966;PMID:10862094;PMID:10973849;PMID:15840476;PMID:19490267;PMID:19716085;PMID:19841300). This is a literature report, and does not necessarily reflect the clinical interpretation of the Imperial College / Royal Brompton Cardiovascular Genetics laboratory. -

Jan 29, 2019

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Gly584Ser variant in KCNH2 has been reported in 4 individuals with long QT syndrome, segregated with disease in at least 11 affected relatives from 2 families (Swan 1999, Laitinen 2000, Zhao 2009, Giudicessi 2012, and Li 2015), and has also been reported by other clinical laboratories in ClinVar (Variation ID: 67261). In vitro functional studies provide some evidence that the p.Gly584Ser variant may impact protein function (Zhao 2009). This variant was absent from large population studies. Computational prediction tools and conservation analysis do not provide strong support for or against an impact to the protein. In summary, although additional studies are required to fully establish its clinical significance, the p.Gly584Ser variant is likely pathogenic. -

Short QT syndrome type 1 Pathogenic:1

Mar 11, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Long QT syndrome Pathogenic:1

Jan 07, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 584 of the KCNH2 protein (p.Gly584Ser). This variant is present in population databases (rs199473428, gnomAD 0.002%). This missense change has been observed in individuals with long QT syndrome (LQTS) (PMID: 10862094, 10973849, 19490267, 22949429, 24606995). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 67261). 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. Experimental studies have shown that this missense change affects KCNH2 function (PMID: 19490267). For these reasons, this variant has been classified as Pathogenic. -

Cardiovascular phenotype Pathogenic:1

Sep 14, 2023

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G584S variant (also known as c.1750G>A), located in coding exon 7 of the KCNH2 gene, results from a G to A substitution at nucleotide position 1750. The glycine at codon 584 is replaced by serine, an amino acid with similar properties, and is located in the S5/pore transmembrane spanning region. This alteration has been detected in long QT syndrome (LQTS) cohorts, a sudden cardiac arrest/death cohort, and cohorts referred for LQTS genetic testing with varying levels of clinical detail (Splawski I et al. Circulation. 2000;102:1178-85; Kapa S et al. Circulation. 2009;120:1752-60; Kapplinger JD et al. Heart Rhythm. 2009;6:1297-303; Stattin EL et al. BMC Cardiovasc Disord. 2012;12:95; Christiansen M et al. BMC Med Genet. 2014;15:31; Li MH et al. Hum Genomics. 2015;9:15; Nakajima T et al. Circ J. 2015;79(6):1185-92). This alteration has been reported to segregate with disease in a family with symptomatic individuals and members with moderate QTc prolongation where, overall, carriers had longer QT intervals than non-carriers; however, some individuals with QT prolongation were not indicated as carriers of this alteration, suggesting that this alteration is associated with reduced phenotypic penetrance (Kerr SM et al. Sci Rep, 2019 Jul;9:10964; Swan H et al. J Am. Coll Cardiol. 1999;34:823-9; Laitinen P et al. Hum Mutat. 2000;15:580-1). In vitro functional studies have suggested this alteration may have some impact on channel function or protein trafficking (Zhao JT et al. J Cardiovasc Electrophysiol. 2009;20:923-30; Perry MD et al. J Physiol Lond. 2016;594:4031-49). Internal analysis indicates this alteration may be structurally disruptive (Wang W et al. Cell. 2017;169(3):422-430.e10). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Short QT syndrome type 1;C3150943:Long QT syndrome 2 Pathogenic:1

Feb 10, 2016

Division of Human Genetics, Children's Hospital of Philadelphia

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

KCNH2-related disorder Pathogenic:1

Nov 24, 2023

Rady Children's Institute for Genomic Medicine, Rady Children's Hospital San Diego

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The KCNH2 gene is constrained against missense variation (Z-score= 3.37), and missense variants are a common mechanism of disease (HGMD, ClinVar database; PMID: 20301308). The c.1750G>A (p.Gly584Ser) variant affects a highly conserved amino acid; however, in silico tools used to predict the effect of this variant on protein function yield discordant results. This variant has been reported in families and individuals with long QT syndrome and is one of the most common alterations in the KCNH2 gene (PMID: 10862094, 10973849, 22949429, 24606995, 32048431, 34319147, 26187847, 19490267, 31358886). Different amino acid changes at the same residue (p.Gly584Arg, p.Gly584Cys, p.Gly584Val) have been previously reported in individuals with long QT syndrome (PMID: 19716085, 18441445, 18752142). Functional studies indicate this variant causes potassium channel gating defects (PMID: 19490267). The c.1750G>A (p.Gly584Ser) variant is present in the heterozygous state in the gnomAD population database at a frequency of 0.001% (2/251412) and thus is presumed to be rare. Based on the available evidence, c.1750G>A (p.Gly584Ser) is classified as Pathogenic. -

Cardiac arrhythmia Pathogenic:1

Jul 14, 2019

Color Diagnostics, LLC DBA Color Health

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces glycine with serine at codon 584 in the extracellular linker region between transmembrane domain S5 and pore-forming region of the KCNH2 protein. Computational prediction tools and conservation analyses suggest that this variant may have deleterious impact on the protein function. Computational splicing tools suggest that this variant may not impact RNA splicing. Experimental functional studies have shown that the mutant protein carrying this variant traffics to the cell membrane normally but has moderate impact on the channel function (PMID: 19490267, 26958806). This variant has been reported to segregate with long QT syndrome in a large multigenerational family (PMID: 19490267). This variant has also been reported in multiple unrelated individuals affected with long QT syndrome (PMID: 10862094, 10973849, 22949429, 23098067, 24606995, 25925977). This variant has been identified in 2/251412 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Based on available evidence, this variant is classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.72
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.48
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	.;D;D
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Pathogenic	0.85	D
MetaRNN	Pathogenic	0.96	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Benign	0.84	.;L;.
PrimateAI	Uncertain	0.63	T
PROVEAN	Pathogenic	-5.9	D;D;.
REVEL	Pathogenic	0.87
Sift	Benign	0.28	T;T;.
Sift4G	Benign	0.24	T;T;T
Polyphen		0.92	P;D;.
Vest4		0.93
MVP		0.99
MPC		2.1
ClinPred		0.98	D
GERP RS		4.4
Varity_R		0.54
gMVP		0.97

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

Other links and lift over

dbSNP: rs199473428; hg19: chr7-150648731; COSMIC: COSV51258331;