rs199473423

Positions:

• chr7-150951678-C-A
• chr7-150951678-C-G
• chr7-150951678-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000238.4(KCNH2):​c.1715G>T​(p.Gly572Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G572C) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 7.54

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 18 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
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-150951679-C-A is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 7-150951678-C-A is Pathogenic according to our data. Variant chr7-150951678-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 67251.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.1715G>T	p.Gly572Val	missense_variant	7/15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.1715G>T	p.Gly572Val	missense_variant	7/15	1	NM_000238.4	ENSP00000262186	P1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 04, 2016

The Gly572Val variant in the KCNH2 gene has been reported previously in one individual with LQTS and it was absent from more than 2,600 reference alleles. Also, the NHLBI ESP Exome Variant Server reports Gly572Val was not observed in approximately 5,000 samples from individuals of European and African American backgrounds, indicating it is not a common benign variant in these populations. Variants in this codon (Gly572Arg, Gly572Asp, Gly572Cys, Gly572Ser) and in nearby codons (Ile571Leu, Ile571Val, Met574Val) have been reported in association with LQTS, further supporting the functional importance of this region of the protein. -

Long QT syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 22, 2023

This sequence change replaces glycine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 572 of the KCNH2 protein (p.Gly572Val). This variant is not present in population databases (gnomAD no frequency). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Gly572 amino acid residue in KCNH2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 15176425, 19490267, 22949429, 27803431). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change affects KCNH2 function (PMID: 25417810). 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: 67251). This missense change has been observed in individuals with clinical features of long QT syndrome (PMID: 19716085, 22949429; Invitae). -

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: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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	.;D;D
Eigen	Pathogenic	0.68
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.8	.;M;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.79	T
PROVEAN	Pathogenic	-8.8	D;D;.
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.99
MutPred		0.93		.;Gain of catalytic residue at G572 (P = 0.0215);.;
MVP		1.0
MPC		2.4
ClinPred		1.0	D
GERP RS		3.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.94
gMVP		0.99

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: rs199473423; hg19: chr7-150648766;