rs864622309

Variant names:

• chr7-150947385-CG-C
• rs864622309
• NM_000238.4:c.3094delC

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.3094delC​(p.Arg1032GlyfsTer25) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. RRP1032SP?) has been classified as Pathogenic. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNH2 NM_000238.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 0.209

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 7-150947385-CG-C is Pathogenic according to our data. Variant chr7-150947385-CG-C is described in ClinVar as [Pathogenic]. Clinvar id is 219924.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr7-150947385-CG-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.3094delC	p.Arg1032GlyfsTer25	frameshift_variant	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.3094delC	p.Arg1032GlyfsTer25	frameshift_variant	Exon 13 of 15	1	NM_000238.4	ENSP00000262186.5
KCNH2	ENST00000330883.9	c.2074delC	p.Arg692GlyfsTer25	frameshift_variant	Exon 9 of 11	1		ENSP00000328531.4
KCNH2	ENST00000684241.1	n.3927delC		non_coding_transcript_exon_variant	Exon 11 of 13

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Apr 12, 2019

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift 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; Not observed in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 19716085, 24530480, 10973849) -

Long QT syndrome Pathogenic:1

Oct 30, 2024

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 (p.Arg1032Glyfs*25) in 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 (PMID: 10973849, 19862833). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with long QT syndrome (PMID: 10973849, 24530480). ClinVar contains an entry for this variant (Variation ID: 219924). For these reasons, this variant has been classified as Pathogenic. -

Cardiovascular phenotype Pathogenic:1

Mar 05, 2019

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.3094delC pathogenic mutation, located in coding exon 13 of the KCNH2 gene, results from a deletion of one nucleotide at nucleotide position 3094, causing a translational frameshift with a predicted alternate stop codon (p.R1032Gfs*25). This alteration (also referred to as G1031fs+24X and G1031fs/24) has been previously reported in association with long QT syndrome, and has been shown to result in nonsense-mediated mRNA decay (Splawski I et al. Circulation. 2000;102:1178-85; Gong Q et al. Gene. 2014;539:190-7). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs864622309; hg19: chr7-150644473;