rs199472917

chr7-150951784-G-A

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000238.4(KCNH2):c.1609C>T(p.Arg537Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000138 in 1,444,274 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R537Q) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2 O:1
• Conservation: PhyloP100: 3.54

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 10 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 9 uncertain in NM_000238.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-150951783-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 200360.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNH2	NM_000238.4	c.1609C>T	p.Arg537Trp	missense_variant	7/15	ENST00000262186.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNH2	ENST00000262186.10	c.1609C>T	p.Arg537Trp	missense_variant	7/15	1	NM_000238.4	P1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000138 AC: 2 AN: 1444274 Hom.: 0 Cov.: 36 AF XY: 0.00 AC XY: 0 AN XY: 715416

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: 0.00000182

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Feb 01, 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 disruptive. ClinVar contains an entry for this variant (Variation ID: 67222). This missense change has been observed in individual(s) with seizures and long QT syndrome (PMID: 19184172). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 537 of the KCNH2 protein (p.Arg537Trp). -

Cardiac arrhythmia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Jan 10, 2020

This missense variant replaces arginine with tryptophan at codon 537 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). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has been reported in compound heterozygous state with a pathogenic truncation variant in an individual affected with a severe, childhood-onset long QT syndrome (PMID: 19184172). The proband's parents were asymptomatic heterozygous carriers. 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. -

Congenital long QT syndrome Other:1

not provided, no classification provided

literature only

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

-

This variant has been reported as associated with Long QT syndrome in the following publications (PMID:19184172). 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	Pathogenic	1.0
CardioboostArm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.53
Cadd	Pathogenic	26
Dann	Uncertain	1.0
Eigen	Uncertain	0.43
Eigen_PC	Benign	0.21
FATHMM_MKL	Uncertain	0.82	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationTaster	Benign	0.92	N;N;N;N
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-7.7	D;D;.
REVEL	Pathogenic	0.80
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.93
MutPred		0.85		.;Gain of helix (P = 0.0349);.;
MVP		1.0
MPC		2.2
ClinPred		1.0	D
GERP RS		0.74
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.92
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: rs199472917; hg19: chr7-150648872; COSMIC: COSV100060484;