7-150951615-A-T

Variant names:

• chr7-150951615-A-T
• rs28928904
• NM_000238.4:c.1778T>A

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000238.4(KCNH2):​c.1778T>A​(p.Ile593Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I593T) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1 O:1
• Conservation: PhyloP100: 9.18
• Publications: 22 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 13 ACMG points.

• PM1: In a hotspot region, there are 12 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 17 uncertain in NM_000238.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-150951615-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 67270.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 158 curated pathogenic missense variants (we use a threshold of 10). The gene has 38 curated benign missense variants. Gene score misZ: 3.3724 (above the threshold of 3.09). Trascript score misZ: 2.4846 (below the threshold of 3.09). GenCC associations: The gene is linked to long QT syndrome 2, Brugada syndrome, short QT syndrome type 1, short QT syndrome, long QT syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984
• PP5: Variant 7-150951615-A-T is Pathogenic according to our data. Variant chr7-150951615-A-T is described in ClinVar as Pathogenic. ClinVar VariationId is 67269.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000238.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNH2	NM_000238.4	MANE Select	c.1778T>A	p.Ile593Lys	missense	Exon 7 of 15	NP_000229.1
	KCNH2	NM_001406753.1		c.1490T>A	p.Ile497Lys	missense	Exon 5 of 13	NP_001393682.1
	KCNH2	NM_172056.3		c.1778T>A	p.Ile593Lys	missense	Exon 7 of 9	NP_742053.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNH2	ENST00000262186.10	TSL:1 MANE Select	c.1778T>A	p.Ile593Lys	missense	Exon 7 of 15	ENSP00000262186.5
	KCNH2	ENST00000330883.9	TSL:1	c.758T>A	p.Ile253Lys	missense	Exon 3 of 11	ENSP00000328531.4
	KCNH2	ENST00000461280.2	TSL:1	n.1076T>A		non_coding_transcript_exon	Exon 3 of 5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251422 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461874 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727238

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53402

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112010

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome Pathogenic:1

Jul 10, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

A different missense substitution at this codon (p.Ile593Arg) has been determined to be pathogenic (PMID: 25417810, 9694858, 23303164, 10973849, 8635257). This suggests that the isoleucine residue is critical for KCNH2 protein function and that other missense substitutions at this position may also be pathogenic. This sequence change replaces isoleucine with lysine at codon 593 of the KCNH2 protein (p.Ile593Lys). The isoleucine residue is moderately conserved and there is a moderate physicochemical difference between isoleucine and lysine. This variant is not present in population databases (rs28928904, ExAC no frequency). This variant has been reported in an individual with long QT syndrome (PMID: 21956039), as well as in an individual referred for long QT syndrome genetic testing (PMID: 19716085). In addition, this variant has been demonstrated to segregate with long QT syndrome in a family (Invitae). ClinVar contains an entry for this variant (Variation ID: 67269). This variant identified in the KCNH2 gene is located in the transmembrane spanning S5/pore region of the resulting protein (PMID: 19841300, 25348405). For more information about the location of this variant, please visit www.invitae.com/KCNH2-topology. Experimental studies have shown that this missense change leads to defecting protein trafficking (PMID: 25417810). For these reasons, this variant has been classified as Pathogenic.

Congenital long QT syndrome Other:1

Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

This variant has been reported as associated with Long QT syndrome in the following publications (PMID:19716085). This is a literature report, and does not necessarily reflect the clinical interpretation of the Imperial College / Royal Brompton Cardiovascular Genetics laboratory.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
CardioboostArm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	27
DANN	Benign	0.97
DEOGEN2	Pathogenic	0.96	D
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		9.2
PrimateAI	Uncertain	0.74	T
PROVEAN	Pathogenic	-5.2	D
REVEL	Pathogenic	0.94
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0040	D
Polyphen		0.65	P
Vest4		0.83
MutPred		0.91		Gain of disorder (P = 0.0022)
MVP		1.0
MPC		2.8
ClinPred		1.0	D
GERP RS		4.3
Varity_R		0.75
gMVP		0.97
Mutation Taster		=7/93	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: rs28928904; hg19: chr7-150648703;