NM_000238.4:c.1911G>C

Variant names:

• chr7-150951482-C-G
• rs199472966
• NM_000238.4:c.1911G>C

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP3_Strong PP5

The NM_000238.4(KCNH2):​c.1911G>C​(p.Glu637Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E637K) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1 O:1
• Conservation: PhyloP100: 3.13

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 11 ACMG points.

• PM1: In a topological_domain Extracellular (size 5) in uniprot entity KCNH2_HUMAN there are 6 pathogenic changes around while only 0 benign (100%) 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 chr7-150951484-C-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.98
• PP5: Variant 7-150951482-C-G is Pathogenic according to our data. Variant chr7-150951482-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 67331.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1, not_provided=1}. Variant chr7-150951482-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.1911G>C	p.Glu637Asp	missense_variant	Exon 7 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.1911G>C	p.Glu637Asp	missense_variant	Exon 7 of 15	1	NM_000238.4	ENSP00000262186.5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 34

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Cardiovascular phenotype Pathogenic:1

Sep 14, 2018

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.E637D variant (also known as c.1911G>C), located in coding exon 7 of the KCNH2 gene, results from a G to C substitution at nucleotide position 1911. The glutamic acid at codon 637 is replaced by aspartic acid, an amino acid with highly similar properties. This alteration has been reported in two long QT syndrome clinical genetic testing cohorts; however, clinical details were limited (Napolitano C et al. JAMA, 2005 Dec;294:2975-80; Kapplinger JD et al. Heart Rhythm, 2009 Sep;6:1297-303). One functional study indicated that this alteration causes a dominant negative trafficking defect (Anderson CL et al. Nat Commun, 2014 Nov;5:5535). Based on internal structural analysis, this variant is anticipated to result in a significant decrease in structural stability (Wang W et al. Cell, 2017 Apr;169:422-430.e10; Ambry internal data). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Long QT syndrome Uncertain:1

Jul 13, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with aspartic acid, which is acidic and polar, at codon 637 of the KCNH2 protein (p.Glu637Asp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Long QT Syndrome (PMID: 16414944, 19716085). ClinVar contains an entry for this variant (Variation ID: 67331). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). Experimental studies have shown that this missense change affects KCNH2 function (PMID: 16414944). This variant disrupts the p.Glu637 amino acid residue in KCNH2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 12062363, 21109023, 21216356, 23022675, 25417810). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

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:16414944;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 v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	.;D;D
Eigen	Uncertain	0.37
Eigen_PC	Uncertain	0.24
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.78	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Pathogenic	0.83	D
MutationAssessor	Pathogenic	3.1	.;M;.
PrimateAI	Pathogenic	0.84	D
PROVEAN	Uncertain	-2.9	D;D;.
REVEL	Pathogenic	0.76
Sift	Pathogenic	0.0	D;D;.
Sift4G	Uncertain	0.0070	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.97
MutPred		0.87		.;Loss of methylation at K638 (P = 0.0832);.;
MVP		1.0
MPC		2.1
ClinPred		0.99	D
GERP RS		1.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.7
Varity_R		0.81
gMVP		1.0

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: rs199472966; hg19: chr7-150648570;