rs794728504

Variant names:

• chr7-150947462-GC-G
• rs794728504
• NM_000238.4:c.3017delG

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.3017delG​(p.Gly1006AlafsTer51) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000705 in 1,418,556 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: KCNH2 NM_000238.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 2.80

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 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 7-150947462-GC-G is Pathogenic according to our data. Variant chr7-150947462-GC-G is described in ClinVar as [Pathogenic]. Clinvar id is 200799.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr7-150947462-GC-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.3017delG	p.Gly1006AlafsTer51	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.3017delG	p.Gly1006AlafsTer51	frameshift_variant	Exon 13 of 15	1	NM_000238.4	ENSP00000262186.5
KCNH2	ENST00000330883.9	c.1997delG	p.Gly666AlafsTer51	frameshift_variant	Exon 9 of 11	1		ENSP00000328531.4
KCNH2	ENST00000684241.1	n.3850delG		non_coding_transcript_exon_variant	Exon 11 of 13

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.05e-7 AC: 1 AN: 1418556 Hom.: 0 Cov.: 36 AF XY: 0.00 AC XY: 0 AN XY: 701434

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: 9.17e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome 2 Pathogenic:1

Aug 21, 2019

Center For Human Genetics And Laboratory Diagnostics, Dr. Klein, Dr. Rost And Colleagues

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Apr 04, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed in large population cohorts (gnomAD); 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; This variant is associated with the following publications: (PMID: 15840476, 15851119, 12877697, 31361068) -

Long QT syndrome Pathogenic:1

Sep 24, 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.Gly1006Alafs*51) 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 individual(s) with KCNH2-related conditions (PMID: 12877697, 15840476). ClinVar contains an entry for this variant (Variation ID: 200799). For these reasons, this variant has been classified as Pathogenic. -

Short QT syndrome type 1;C3150943:Long QT syndrome 2 Pathogenic:1

Mar 30, 2021

Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

KCNH2 NM_000238.3 exon 13 p.Gly1006Alafs*51 (c.3017delG): This variant has been reported in the literature in at least 3 individuals with LQTS (Nemec 2003 PMID:12877697 ). This variant is not present in large control databases but is present in ClinVar (Variation ID:200799). Evolutionary conservation and computational predictive tools for this variant are limited or unavailable. This variant creates a premature stop codon 51 amino acids downstream from this location which results in an absent or abnormal protein. Loss of function variants are a known mechanism of disease for this gene (Hedley 2009 PMID:19862833). In summary, this variant is classified as pathogenic based on the data above. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs794728504; hg19: chr7-150644550;