rs199472973

chr7-150951458-C-T

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.1935G>A(p.Met645Ile) 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M645L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 34)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: 7.80

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 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 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 chr7-150951460-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 869431.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNH2	NM_000238.4	c.1935G>A	p.Met645Ile	missense_variant	7/15	ENST00000262186.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNH2	ENST00000262186.10	c.1935G>A	p.Met645Ile	missense_variant	7/15	1	NM_000238.4	P1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 11, 2018

A variant of uncertain significance has been identified in the KCNH2 gene. The M645I variant hasbeen previously reported in association with LQTS (Kapplinger et al., 2009; Issa et al., 2015). TheM645I variant was not observed in approximately 6,500 individuals of European and AfricanAmerican ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benignvariant in these populations. This substitution occurs at a position that is conserved across species, andin silico analysis predicts this variant is probably damaging to the protein structure/function. Missensevariants in the same residue (M645V, M645L, M645R) and in nearby residues (F640V, F640L, S641F,V644L, G648S, S649P) have been reported in the Human Gene Mutation Database in association withLQTS (Stenson et al., 2014). Nevertheless, the M645I variant is a conservative amino acidsubstitution, which is not likely to impact secondary protein structure as these residues share similarproperties. Thus, this variant lacks observation in a significant number of affected individuals,segregation data, and functional evidence, which would further clarify its pathogenicity. -

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). 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	0.56	D
BayesDel_noAF	Pathogenic	0.56
Cadd	Pathogenic	29
Dann	Uncertain	1.0
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.58
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.90	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.83	D
PROVEAN	Uncertain	-3.9	D;D;.
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;.
Sift4G	Uncertain	0.0050	D;D;D
Polyphen		0.99	D;D;.
Vest4		0.94
MutPred		0.91		.;Loss of sheet (P = 0.1907);.;
MVP		1.0
MPC		2.1
ClinPred		1.0	D
GERP RS		4.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.7
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: rs199472973; hg19: chr7-150648546;