Genetic Variant KCNH2:p.Cys977Trp (chr7-150947640-G-C) – ACMG Classification: Likely_benign (-3 pts)

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 0P and 3B. BP4_ModerateBS2_Supporting

The NM_000238.4(KCNH2):c.2931C>G(p.Cys977Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000411 in 1,459,836 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C977F) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: -1.56

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:

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.23435184).

BS2

High AC in GnomAdExome4 at 6 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.2931C>G	p.Cys977Trp	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.2931C>G	p.Cys977Trp	missense_variant	Exon 12 of 15	1	NM_000238.4	ENSP00000262186.5	Q12809-1
KCNH2	ENST00000330883.9 link	c.1911C>G	p.Cys637Trp	missense_variant	Exon 8 of 11	1		ENSP00000328531.4	Q12809-2
KCNH2	ENST00000684241.1 link	n.3764C>G		non_coding_transcript_exon_variant	Exon 10 of 13

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000823

AC:

AN:

243142

Hom.:

AF XY:

0.00000755

AC XY:

AN XY:

132402

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000553

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000917

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000411

AC:

AN:

1459836

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

726138

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000101

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000180

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Bravo

AF:

0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Long QT syndrome

Uncertain:1

Sep 05, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant of Uncertain Significance due to insufficient evidence: This missense variant is located in the C-terminal cytoplasmic domain of the KCNH2 protein. Computational prediction tools and conservation analyses are inconclusive regarding the impact of this variant on the protein function. Computational splicing tools suggest that this variant may not impact RNA splicing. To our knowledge, functional assays have not been performed for this variant nor has this variant been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 2/238672 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Available evidence is insufficient to determine the role of this variant in disease conclusively. -

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

Uncertain:1

Mar 10, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiac arrhythmia

Uncertain:1

Jan 15, 2019

Color Diagnostics, LLC DBA Color Health

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

Benign

-0.041

BayesDel_noAF

Benign

-0.12

CADD

Benign

0.84

DANN

Benign

0.67

DEOGEN2

Uncertain

0.43

.;T

Eigen

Benign

-1.6

Eigen_PC

Benign

-1.7

FATHMM_MKL

Benign

0.060

LIST_S2

Benign

0.72

T;T

M_CAP

Pathogenic

0.79

MetaRNN

Benign

0.23

T;T

MetaSVM

Uncertain

0.31

MutationAssessor

Benign

0.0

.;N

PrimateAI

Benign

0.48

PROVEAN

Benign

-1.1

N;N

REVEL

Uncertain

0.47

Sift

Benign

0.20

T;T

Sift4G

Benign

0.19

T;T

Polyphen

0.50

P;B

Vest4

0.35

MutPred

0.26

.;Gain of helix (P = 0.062);

MVP

0.72

MPC

0.28

ClinPred

0.065

GERP RS

-9.5

Varity_R

0.10

gMVP

0.60

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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