7-150952564-G-A

Position:

• chr7-150952564-G-A

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PP3_Strong PP5_Moderate

The NM_000238.4(KCNH2):​c.1418C>T​(p.Thr473Ile) 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. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.80

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 topological_domain Cytoplasmic (size 23) in uniprot entity KCNH2_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_000238.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.95
• PP5: Variant 7-150952564-G-A is Pathogenic according to our data. Variant chr7-150952564-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 811073.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.1418C>T	p.Thr473Ile	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.1418C>T	p.Thr473Ile	missense_variant	6/15	1	NM_000238.4	ENSP00000262186.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Jul 24, 2018

The KCNH2 c.1418C>T; p.Thr473Ile variant, to our knowledge, is not reported in the medical literature or gene specific databases. Other variants at this codon (p.Thr473Pro, p.Thr473Asn), as well as an adjacent p.Thr474Ile variant, have been reported in individuals with Long QT syndrome and are considered pathogenic (Itoh 2010, Kapplinger 2009, Liu 2013, Tanaka 1997). Electrophysiological characterization of the p.Thr473Pro and p.Thr474Ile variants reveal dominant negative effects on channel activity and altered gating properties, respectively (Liu 2013, Zhou 1998), suggesting that the S2-S3 cytoplasmic loop containing Thr473 is functionally important. The c.1418C>T; p.Thr473Ile variant is absent from general population databases (1000 Genomes Project, Exome Variant Server, and Genome Aggregation Database), indicating it is not a common polymorphism. The threonine at codon 473 is highly conserved and computational analyses (SIFT, PolyPhen-2) predict that this variant is deleterious. Based on available information, this variant is considered to be likely pathogenic. References: Itoh H et al. Long QT syndrome with compound mutations is associated with a more severe phenotype: a Japanese multicenter study. Heart Rhythm. 2010 Oct;7(10):1411-8. Kapplinger JD et al. Spectrum and prevalence of mutations from the first 2,500 consecutive unrelated patients referred for the FAMILION long QT syndrome genetic test. Heart Rhythm. 2009 Sep;6(9):1297-303. Liu L et al. A novel mutation in the transmembrane nonpore region of the KCNH2 gene causes severe clinical manifestations of long QT syndrome. Heart Rhythm. 2013 Jan;10(1):61-7. Tanaka T et al. Four novel KVLQT1 and four novel HERG mutations in familial long-QT syndrome. Circulation. 1997 Feb 4;95(3):565-7. Zhou Z et al. HERG channel dysfunction in human long QT syndrome. Intracellular transport and functional defects. J Biol Chem. 1998 Aug 14;273(33):21061-6. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.98	.;D;D
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.95	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	.;H;.
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-5.6	D;D;.
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.99
MutPred		0.73		.;Loss of disorder (P = 0.0796);.;
MVP		1.0
MPC		2.3
ClinPred		1.0	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.7
Varity_R		0.89
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: rs199472905; hg19: chr7-150649652;