7-150974783-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 3P and 4B. PM1PP2BS2

The NM_000238.4(KCNH2):c.235G>A(p.Ala79Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000757 in 1,452,944 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. A79S) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 34)

Exomes 𝑓: 0.0000076 ( 0 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 0.146

Publications

1 publications found

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 Gene-Disease associations (from GenCC):

long QT syndrome
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
long QT syndrome 2
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
short QT syndrome
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
short QT syndrome type 1
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
Brugada syndrome
Inheritance: AD Classification: MODERATE, NO_KNOWN Submitted by: ClinGen, Genomics England PanelApp

KCNH2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

PM1

In a hotspot region, there are 15 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 24 uncertain in NM_000238.4

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 158 curated pathogenic missense variants (we use a threshold of 10). The gene has 38 curated benign missense variants. Gene score misZ: 3.3724 (above the threshold of 3.09). Trascript score misZ: 2.4846 (below the threshold of 3.09). GenCC associations: The gene is linked to long QT syndrome 2, Brugada syndrome, short QT syndrome type 1, short QT syndrome, long QT syndrome.

BS2

High AC in GnomAdExome4 at 11 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4 link	c.235G>A	p.Ala79Thr	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 link	c.235G>A	p.Ala79Thr	missense_variant	Exon 2 of 15	1	NM_000238.4	ENSP00000262186.5

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000437

AC:

AN:

228884

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000299

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000757

AC:

AN:

1452944

Hom.:

Cov.:

AF XY:

0.0000125

AC XY:

AN XY:

722236

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33206

American (AMR)

AF:

0.0000227

AC:

AN:

44120

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25896

East Asian (EAS)

AF:

0.00

AC:

AN:

39318

South Asian (SAS)

AF:

0.00

AC:

AN:

85414

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51912

Middle Eastern (MID)

AF:

0.000198

AC:

AN:

5054

European-Non Finnish (NFE)

AF:

0.00000722

AC:

AN:

1108214

Other (OTH)

AF:

0.0000167

AC:

AN:

59810

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000283

Hom.:

Bravo

AF:

0.00000378

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

May 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 79 of the KCNH2 protein (p.Ala79Thr). 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: 987798). 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. -

Jan 11, 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 alanine with threonine at codon 79 of the KCNH2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 1/228884 chromosomes 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 specified

Uncertain:1

Nov 30, 2020

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: KCNH2 c.235G>A (p.Ala79Thr) results in a non-conservative amino acid change located in the PAS domain (IPR000014) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4.4e-06 in 228884 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.235G>A in individuals affected with Arrhythmia and no experimental evidence demonstrating its impact on protein function have been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

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

Uncertain:1

Aug 25, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Cardiac arrhythmia

Uncertain:1

Apr 05, 2021

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

0.093

CardioboostArm

Benign

0.00057

BayesDel_addAF

Uncertain

0.086

BayesDel_noAF

Benign

-0.11

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.58

D;T

Eigen

Benign

-0.50

Eigen_PC

Benign

-0.38

FATHMM_MKL

Benign

0.63

LIST_S2

Uncertain

0.86

D;D

M_CAP

Pathogenic

0.97

MetaRNN

Uncertain

0.56

D;D

MetaSVM

Pathogenic

0.99

MutationAssessor

Benign

0.36

N;.

PhyloP100

0.15

PrimateAI

Pathogenic

0.86

PROVEAN

Benign

-0.43

N;.

REVEL

Uncertain

0.48

Sift

Uncertain

0.019

D;.

Sift4G

Benign

0.090

T;T

Polyphen

0.0

B;.

Vest4

0.56

MutPred

0.43

Gain of phosphorylation at A79 (P = 0.035);.;

MVP

0.55

MPC

1.1

ClinPred

0.52

GERP RS

4.4

Varity_R

0.24

gMVP

0.88

Mutation Taster

=39/61

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over