7-150951506-G-T

Position:

• chr7-150951506-G-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_000238.4(KCNH2):​c.1887C>A​(p.Asn629Lys) variant causes a missense change involving the alteration of a non-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. N629D) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1 O:1
• Conservation: PhyloP100: 0.163

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 12 ACMG points.

• PM1: In a intramembrane_region Pore-forming; Name=Segment H5 (size 20) in uniprot entity KCNH2_HUMAN there are 23 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 chr7-150951508-T-C is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 7-150951506-G-T is Pathogenic according to our data. Variant chr7-150951506-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 67317.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr7-150951506-G-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.1887C>A	p.Asn629Lys	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.1887C>A	p.Asn629Lys	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: Likely pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 08, 2021

Experimental studies have shown that this variant affects KCNH2 function (PMID: 10517660, 25417810). 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.Asn629 amino acid residue in KCNH2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10973849, 16432067, 17905336, 19841300). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 67317). This variant has been observed in individuals with long QT syndrome (PMID: 10517660; Invitae). This variant is not present in population databases (ExAC no frequency). This sequence change replaces asparagine with lysine at codon 629 of the KCNH2 protein (p.Asn629Lys). The asparagine residue is highly conserved and there is a moderate physicochemical difference between asparagine and lysine. -

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:10517660). 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	0.23	D
BayesDel_noAF	Uncertain	0.090
CADD	Benign	20
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.98	.;D;D
Eigen	Benign	-0.23
Eigen_PC	Benign	-0.48
FATHMM_MKL	Uncertain	0.79	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.84	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Pathogenic	3.2	.;M;.
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-5.8	D;D;.
REVEL	Pathogenic	0.77
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.99
MutPred		0.92		.;Gain of ubiquitination at N629 (P = 0.0101);.;
MVP		0.96
MPC		2.3
ClinPred		1.0	D
GERP RS		-4.8
Varity_R		0.95
gMVP		1.0

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: rs41307295; hg19: chr7-150648594;