rs886039183

Positions:

• chr7-150974806-C-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000238.4(KCNH2):​c.212G>A​(p.Gly71Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G71R) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.75

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-150974807-C-G is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.944
• PP5: Variant 7-150974806-C-T is Pathogenic according to our data. Variant chr7-150974806-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 264521.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.212G>A	p.Gly71Glu	missense_variant	2/15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.212G>A	p.Gly71Glu	missense_variant	2/15	1	NM_000238.4	ENSP00000262186.5
KCNH2	ENST00000532957.5	n.435G>A		non_coding_transcript_exon_variant	2/9	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 13, 2023

This sequence change replaces glycine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 71 of the KCNH2 protein (p.Gly71Glu). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with long QT syndrome (PMID: 23631430; Invitae). ClinVar contains an entry for this variant (Variation ID: 264521). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects KCNH2 function (PMID: 35688148). This variant disrupts the p.Gly71 amino acid residue in KCNH2. Other variant(s) that disrupt this residue have been observed in individuals with KCNH2-related conditions (PMID: 26496715, 29497013; Invitae), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. -

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 27, 2015

The p.G71E variant (also known as c.212G>A), located in coding exon 2 of the KCNH2 gene, results from a G to A substitution at nucleotide position 212. The glycine at codon 71 is replaced by glutamic acid, an amino acid with some similar properties. This variant has been reported in patients referred for long QT syndrome (LQTS) genetic testing; however, one patient also carried a variant in the SCN5A gene (Lieve KV et al. Genet Test Mol Biomarkers. 2013;17(7):553-61). This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6486 samples (12972 alleles) with coverage at this position. Other alterations affecting the same amino acid (p.G71R (c.211G>C) and p.G71R (c.211G>A)) have also been reported in association with LQTS (Napolitano C et al. JAMA. 2005 Dec; 294(23):2975-80; Lieve KV et al. Genet Test Mol Biomarkers. 2013;17(7):553-61). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;D
Eigen	Pathogenic	0.72
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.94	D;D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Pathogenic	3.7	H;.
PrimateAI	Pathogenic	0.95	D
PROVEAN	Pathogenic	-5.3	D;.
REVEL	Pathogenic	0.92
Sift	Uncertain	0.0010	D;.
Sift4G	Pathogenic	0.0	D;D
Polyphen		0.97	D;.
Vest4		0.85
MutPred		0.70		Gain of disorder (P = 0.0882);.;
MVP		1.0
MPC		2.4
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.95
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: rs886039183; hg19: chr7-150671894;