rs199472889

Positions:

• chr7-150957394-T-A
• chr7-150957394-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000238.4(KCNH2):​c.1025A>T​(p.Asp342Val) 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 not provided (no stars). Synonymous variant affecting the same amino acid position (i.e. D342D) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: not provided no classification provided O:1
• Conservation: PhyloP100: 7.97

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.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 uncertain in NM_000238.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.909

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNH2	NM_000238.4	c.1025A>T	p.Asp342Val	missense_variant	5/15	ENST00000262186.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNH2	ENST00000262186.10	c.1025A>T	p.Asp342Val	missense_variant	5/15	1	NM_000238.4	P1
KCNH2	ENST00000532957.5	n.1248A>T		non_coding_transcript_exon_variant	5/9	2
KCNH2	ENST00000684241.1	n.1858A>T		non_coding_transcript_exon_variant	3/13

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: not provided

Submissions summary: Other:1

Revision: no classification provided

Submissions by phenotype

Acquired 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 acquired long QT syndrome in the following publications (PMID:19843919). 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	0.87
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.81	D;T
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.61
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.90	D;D
M_CAP	Pathogenic	0.32	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Uncertain	0.56	D
MutationAssessor	Uncertain	2.1	M;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.65	T
PROVEAN	Pathogenic	-4.9	D;.
REVEL	Pathogenic	0.89
Sift	Uncertain	0.0010	D;.
Sift4G	Benign	0.064	T;T
Polyphen		1.0	D;.
Vest4		0.73
MutPred		0.81		Loss of loop (P = 0.0112);.;
MVP		1.0
MPC		2.5
ClinPred		0.99	D
GERP RS		4.8
Varity_R		0.53
gMVP		0.86

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs199472889; hg19: chr7-150654482;