rs199472842

Variant names:

• chr7-150974861-C-A
• NM_000238.4:c.157G>T

Your query was ambiguous. Multiple possible variants found:

• chr7-150974861-C-A
• chr7-150974861-C-G
• chr7-150974861-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_001406755.1(KCNH2):​c.-21G>T variant causes a 5 prime UTR premature start codon gain change. 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).

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNH2 NM_001406755.1 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 6.03

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 Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983
• PP5: Variant 7-150974861-C-A is Pathogenic according to our data. Variant chr7-150974861-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 1499003.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.157G>T	p.Gly53Cys	missense_variant	Exon 2 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.157G>T	p.Gly53Cys	missense_variant	Exon 2 of 15	1	NM_000238.4	ENSP00000262186.5
KCNH2	ENST00000532957.5	n.380G>T		non_coding_transcript_exon_variant	Exon 2 of 9	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 25, 2020

The p.G53C variant (also known as c.157G>T), located in coding exon 2 of the KCNH2 gene, results from a G to T substitution at nucleotide position 157. The glycine at codon 53 is replaced by cysteine, an amino acid with highly dissimilar properties. Based on internal structural analysis, this alteration is located within the PAS domain of KCNH2 and is expected to disrupt trafficking and lead to deactivation of the potassium channel (Chen J et al. J. Biol. Chem., 1999 Apr;274:10113-8; Ambry internal data). This alteration is expected to be more disruptive than p.G53R, an alternate amino acid substitution at this position that has been reported in a patient with Long QT Syndrome Type 2 (LQT2), indicating this codon may be a hotspot location (Haraguchi Y et al. Circ. J., 2005 Jan;69:78-82). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). 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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 07, 2022

This variant disrupts the p.Gly53 amino acid residue in KCNH2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10187793, 10973849, 21536673, 22396785). 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. 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: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This sequence change replaces glycine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 53 of the KCNH2 protein (p.Gly53Cys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Long QT syndrome (Invitae). ClinVar contains an entry for this variant (Variation ID: 1499003). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.50
CADD	Pathogenic	30
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.98	D
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	4.5	H
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-5.8	D
REVEL	Pathogenic	0.92
Sift	Uncertain	0.0070	D
Sift4G	Uncertain	0.0020	D
Polyphen		0.14	B
Vest4		0.69
MutPred		0.87		Loss of loop (P = 0.1242);
MVP		1.0
MPC		1.3
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.92
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

No publications associated with this variant yet.

Other links and lift over

hg19: chr7-150671949;