rs199473511

Positions:

• chr7-150952586-C-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000238.4(KCNH2):​c.1396G>T​(p.Asp466Tyr) 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. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: 7.75

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.1396G>T	p.Asp466Tyr	missense_variant	6/15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.1396G>T	p.Asp466Tyr	missense_variant	6/15	1	NM_000238.4	ENSP00000262186	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 15, 2023

The p.D466Y variant (also known as c.1396G>T), located in coding exon 6 of the KCNH2 gene, results from a G to T substitution at nucleotide position 1396. The aspartic acid at codon 466 is replaced by tyrosine, an amino acid with highly dissimilar properties. This alteration has been reported in a long QT syndrome genetic testing cohort; however, clinical details were limited (Kapplinger JD et al. Heart Rhythm, 2009 Sep;6:1297-303). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

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
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	.;D;D
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.7	.;H;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-8.4	D;D;.
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;.
Vest4		1.0
MutPred		0.93		.;Gain of catalytic residue at F471 (P = 0.4889);.;
MVP		1.0
MPC		2.4
ClinPred		1.0	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.7
Varity_R		0.99
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: rs199473511; hg19: chr7-150649674; COSMIC: COSV51194427;