7-150947477-C-T

Variant names:

• chr7-150947477-C-T
• rs121912509
• NM_000238.4:c.3003G>A

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000238.4(KCNH2):​c.3003G>A​(p.Trp1001*) variant causes a stop gained change. 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 Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: KCNH2 NM_000238.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 5.86

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 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-150947477-C-T is Pathogenic according to our data. Variant chr7-150947477-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 14431.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.3003G>A	p.Trp1001*	stop_gained	Exon 13 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.3003G>A	p.Trp1001*	stop_gained	Exon 13 of 15	1	NM_000238.4	ENSP00000262186.5
KCNH2	ENST00000330883.9	c.1983G>A	p.Trp661*	stop_gained	Exon 9 of 11	1		ENSP00000328531.4
KCNH2	ENST00000684241.1	n.3836G>A		non_coding_transcript_exon_variant	Exon 11 of 13

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1427632 Hom.: 0 Cov.: 36 AF XY: 0.00 AC XY: 0 AN XY: 706916

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome 2 Pathogenic:1

Jul 26, 2002

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

not provided Pathogenic:1

Oct 06, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Has been reported in individuals with LQTS (PMID: 11854117, 23995044); Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies suggest the p.(W1001*) variant results in a truncated protein and significant reduction in channel current properties (PMID: 12021266); Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 11686910, 11854117, 23995044, 17576861, 12021266) -

Long QT syndrome Pathogenic:1

Aug 16, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal at codon 1001 (p.Trp1001*) of the KCNH2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in KCNH2 are known to be pathogenic. There are two different nucleotide changes (c.3002G>A and c.3003G>A) that result in the same amino acid change to a stop codon. The variant c.3002G>A has been classified as pathogenic (Invitae database). This protein change has been reported in the literature in individuals affected with long QT syndrome (PMID: 12021266, 26846766, 11854117). Experimental studies have shown that this nonsense change (p.Tryp1001*) results in reduced mRNA levels due to nonsense-mediated decay and the resulting protein is truncated, which results in a channel with reduced current amplitude (PMID: 17576861, 12021266). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	48
DANN	Uncertain	1.0
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Uncertain	0.93	D
Vest4		0.93
GERP RS		4.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.17		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: rs121912509; hg19: chr7-150644565;