rs794728458

Variant names:

• chr7-150947785-TC-T
• rs794728458
• NM_000238.4:c.2785delG

Your query was ambiguous. Multiple possible variants found:

• chr7-150947785-TC-T
• chr7-150947785-TC-TCC

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000238.4(KCNH2):​c.2785delG​(p.Glu929ArgfsTer45) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000723 in 1,382,686 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: 7.2e-7 (0 hom.)
• Consequence: KCNH2 NM_000238.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 1.34
• Publications: 2 publications found

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]

KCNH2 Gene-Disease associations (from GenCC):

• long QT syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• long QT syndrome 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• short QT syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• short QT syndrome type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• Brugada syndrome

  Inheritance: AD Classification: MODERATE, NO_KNOWN Submitted by: ClinGen, Genomics England PanelApp

ACMG classification

Our verdict: Pathogenic. The variant received 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 7-150947785-TC-T is Pathogenic according to our data. Variant chr7-150947785-TC-T is described in ClinVar as Pathogenic. ClinVar VariationId is 972416.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.2785delG	p.Glu929ArgfsTer45	frameshift_variant	Exon 12 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.2785delG	p.Glu929ArgfsTer45	frameshift_variant	Exon 12 of 15	1	NM_000238.4	ENSP00000262186.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.23e-7 AC: 1 AN: 1382686 Hom.: 0 Cov.: 36 AF XY: 0.00 AC XY: 0 AN XY: 681838

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 31428

American (AMR) AF: 0.00 AC: 0 AN: 35538

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25064

East Asian (EAS) AF: 0.00 AC: 0 AN: 35626

South Asian (SAS) AF: 0.00 AC: 0 AN: 78984

European-Finnish (FIN) AF: 0.0000267 AC: 1 AN: 37390

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4192

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1076874

Other (OTH) AF: 0.00 AC: 0 AN: 57590

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Feb 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

KCNH2: PVS1, PM2 -

Long QT syndrome Pathogenic:1

Jun 21, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 972416). This variant is also known as 2784delG, (p.G928fs+44X). This premature translational stop signal has been observed in individual(s) with long QT syndrome (PMID: 19716085). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Glu929Argfs*45) 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). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		1.3
Mutation Taster		=0/200	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs794728458; hg19: chr7-150644873;