Genetic Variant KCNH2:p.Gly924Arg (chr7-150947801-C-T) – ACMG Classification: Likely_benign (-1 pts)

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 0P and 1B. BS2_Supporting

The NM_000238.4(KCNH2):c.2770G>A(p.Gly924Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000588 in 1,530,634 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000029 ( 0 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 0.618

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

BS2

High AC in GnomAd4 at 5 AD,Digenic gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4 link	c.2770G>A	p.Gly924Arg	missense_variant	Exon 12 of 15	ENST00000262186.10	NP_000229.1	Q12809-1Q15BH2A0A090N8Q0

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
KCNH2	ENST00000262186.10 link	c.2770G>A	p.Gly924Arg	missense_variant	Exon 12 of 15	1	NM_000238.4	ENSP00000262186.5	Q12809-1
KCNH2	ENST00000330883.9 link	c.1750G>A	p.Gly584Arg	missense_variant	Exon 8 of 11	1		ENSP00000328531.4	Q12809-2
KCNH2	ENST00000684241.1 link	n.3603G>A		non_coding_transcript_exon_variant	Exon 10 of 13

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152166

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000290

AC:

AN:

1378468

Hom.:

Cov.:

AF XY:

0.00000294

AC XY:

AN XY:

679460

show subpopulations

Gnomad4 AFR exome

AF:

0.000127

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74334

show subpopulations

Gnomad4 AFR

AF:

0.000121

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000227

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Long QT syndrome

Uncertain:2

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 924 of the KCNH2 protein (p.Gly924Arg). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with KCNH2-related conditions. ClinVar contains an entry for this variant (Variation ID: 200492). 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 tolerated. 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. -

Apr 25, 2024

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces glycine with arginine at codon 924 of the KCNH2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual suspected of having long QT syndrome (ClinVar SCV000234193.9). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

not provided

Uncertain:1

Sep 26, 2018

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The G924R variant has not been published as a mutation or been reported as a benign polymorphism to our knowledge. This variant has been previously identified at GeneDx in an individual referred for testing of LQTS. The G924R variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. Furthermore, this substitution occurs at a position that is conserved in mammals. Located within the cytoplasmic topological domain of the KCNH2 gene, missense mutations in the same residue as this variant (G924A, G924E) and several mutations in nearby residues (R920W, R920Q, R922W, R922Q, G925R, W927G) have been reported in the Human Gene Mutation Database in association with arrhythmia (Stenson et al., 2014), further supporting the functional importance of this residue and region of the protein. Nevertheless, in silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. The G924R variant was not observed in approximately 3,700 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic mutation or a rare benign variant -

Cardiovascular phenotype

Uncertain:1

Mar 07, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G924R variant (also known as c.2770G>A), located in coding exon 12 of the KCNH2 gene, results from a G to A substitution at nucleotide position 2770. The glycine at codon 924 is replaced by arginine, an amino acid with dissimilar properties, and is located in the C-terminal region. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Short QT syndrome type 1;C3150943:Long QT syndrome 2

Uncertain:1

Sep 29, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.10

BayesDel_addAF

Pathogenic

0.34

BayesDel_noAF

Pathogenic

0.26

CADD

Benign

DANN

Uncertain

1.0

DEOGEN2

Benign

0.32

.;T

Eigen

Benign

0.12

Eigen_PC

Benign

0.097

FATHMM_MKL

Benign

0.15

LIST_S2

Benign

0.82

T;T

M_CAP

Pathogenic

0.73

MetaRNN

Uncertain

0.55

D;D

MetaSVM

Pathogenic

0.87

MutationAssessor

Benign

0.55

.;N

PrimateAI

Uncertain

0.70

PROVEAN

Benign

-0.64

N;N

REVEL

Uncertain

0.55

Sift

Benign

0.27

T;T

Sift4G

Benign

0.68

T;T

Polyphen

1.0

D;D

Vest4

0.39

MutPred

0.44

.;Gain of MoRF binding (P = 0.0183);

MVP

0.98

MPC

0.23

ClinPred

0.62

GERP RS

5.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.19

gMVP

0.55

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over