rs864622174

Positions:

• chr7-150947419-TG-T
• chr7-150947419-TG-TGG

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.3060del​(p.Ser1021AlafsTer36) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000151 in 1,325,136 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000015 (0 hom.)
• Consequence: KCNH2 NM_000238.4 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: -0.174

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 7-150947419-TG-T is Pathogenic according to our data. Variant chr7-150947419-TG-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 219597.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr7-150947419-TG-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNH2	NM_000238.4	c.3060del	p.Ser1021AlafsTer36	frameshift_variant	13/15	ENST00000262186.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNH2	ENST00000262186.10	c.3060del	p.Ser1021AlafsTer36	frameshift_variant	13/15	1	NM_000238.4	P1
KCNH2	ENST00000330883.9	c.2040del	p.Ser681AlafsTer36	frameshift_variant	9/11	1
KCNH2	ENST00000684241.1	n.3893del		non_coding_transcript_exon_variant	11/13

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000151 AC: 2 AN: 1325136 Hom.: 0 Cov.: 37 AF XY: 0.00000152 AC XY: 1 AN XY: 656690

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: 9.82e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome 2 Pathogenic:1

Likely pathogenic, no assertion criteria provided

research

deCODE genetics, Amgen

Jul 21, 2023

The variant NM_000238.4:c.3060del (chr7:150947419) in KCNH2 was detected in 2 heterozygotes out of 58K WGS Icelanders (MAF= 0,002%). This variant has been reported in ClinVar previously as pathogenic. Based on ACMG criteria (PVS1, PM2) this variant classifies as likely pathogenic. -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Oct 13, 2023

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 at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 23631430) -

Long QT syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Nov 07, 2017

This variant has been reported in one individual with long QT syndrome (PMID: 23631430). ClinVar contains an entry for this variant (Variation ID: 219597). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Ser1021Alafs*36) 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: 19862833). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

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: rs864622174; hg19: chr7-150644507;