chr7-150951568-C-T

Position:

• chr7-150951568-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.1825G>A​(p.Asp609Asn) variant causes a missense change. 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D609G) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 6.05

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 (HGNC:):

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 chr7-150951567-T-C is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.975
• PP5: Variant 7-150951568-C-T is Pathogenic according to our data. Variant chr7-150951568-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 67286.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr7-150951568-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.1825G>A	p.Asp609Asn	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.1825G>A	p.Asp609Asn	missense_variant	7/15	1	NM_000238.4	ENSP00000262186.5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 34

ClinVar

Significance: 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 31, 2016

The D609N pathogenic variant in the KCNH2 gene has been reported in association with LQTS(Splawski et al., 2000; Lupoglazoff et al., 2001; Moss et al., 2002; Westenskow et al., 2004; Zhang etal., 2008). In addition, functional studies show that the D609N variant does result in deficient proteintrafficking (Anderson et al., 2014). The D609N variant results in a semi-conservative amino acidsubstitution at a position that is conserved across species. Variants in the same residue (D609H,D609Y, D609G) and in nearby residues (G604S, T613A, T613M) have been reported in HGMD inassociation with LQTS (Stenson et al., 2014), further supporting the functional importance of thisregion of the protein. Furthermore, the D609N pathogenic variant was not observed in approximately6,500 individuals of European and African American ancestry in the NHLBI Exome SequencingProject, indicating it is not a common benign variant in these populations. Therefore, we interpret the D609N variant as pathogenic. -

Long QT syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 12, 2023

This sequence change replaces aspartic acid, which is acidic and polar, with asparagine, which is neutral and polar, at codon 609 of the KCNH2 protein (p.Asp609Asn). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with long QT syndrome (PMID: 10973849, 11222472, 11854117, 18808722, 26669661). ClinVar contains an entry for this variant (Variation ID: 67286). 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: 25417810). This variant disrupts the p.Asp609 amino acid residue in KCNH2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 15500450, 25417810). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

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:10973849;PMID:11222472;PMID:11854117;PMID:15051636). 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	0.96
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.060
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.94	.;D;D
Eigen	Uncertain	0.28
Eigen_PC	Uncertain	0.28
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Uncertain	0.97	D;D;D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	0.97	D;D;D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Benign	1.8	.;L;.
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-4.3	D;D;.
REVEL	Pathogenic	0.80
Sift	Uncertain	0.0080	D;D;.
Sift4G	Uncertain	0.046	D;D;T
Polyphen		0.22	B;P;.
Vest4		0.88
MutPred		0.87		.;Loss of ubiquitination at K610 (P = 0.0587);.;
MVP		0.97
MPC		2.2
ClinPred		0.99	D
GERP RS		3.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.7
Varity_R		0.55
gMVP		0.97

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs199472941; hg19: chr7-150648656;