NM_000238.4:c.383A>G

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.383A>G(p.Asn128Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000167 in 1,613,958 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. N128T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000016 ( 0 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 7.47

Publications

0 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 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 15 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 23 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4 link	c.383A>G	p.Asn128Ser	missense_variant	Exon 3 of 15	ENST00000262186.10	NP_000229.1	Q12809-1Q15BH2A0A090N8Q0

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10 link	c.383A>G	p.Asn128Ser	missense_variant	Exon 3 of 15	1	NM_000238.4	ENSP00000262186.5		Q12809-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152074

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000725

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:

0.000478

GnomAD2 exomes

AF:

0.00000795

AC:

AN:

251450

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000157

AC:

AN:

1461884

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.0000187

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000180

AC:

AN:

1112006

Other (OTH)

AF:

0.0000166

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.505

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

AF:

0.0000263

AC:

AN:

152074

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74286

show subpopulations

African (AFR)

AF:

0.0000725

AC:

AN:

41406

American (AMR)

AF:

0.00

AC:

AN:

15276

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5178

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67996

Other (OTH)

AF:

0.000478

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.513

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.0000579

Hom.:

Bravo

AF:

0.0000264

ExAC

AF:

0.0000165

AC:

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

Mar 24, 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 asparagine with serine at codon 128 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). Splice site prediction tools suggest that this variant may impact RNA splicing. 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 2/251450 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. -

Aug 28, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 128 of the KCNH2 protein (p.Asn128Ser). This variant is present in population databases (rs200343670, gnomAD 0.007%). 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: 191473). 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. -

not provided

Uncertain:1

Jun 24, 2013

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:research

- -

Cardiovascular phenotype

Uncertain:1

Jun 28, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.N128S variant (also known as c.383A>G), located in coding exon 3 of the KCNH2 gene, results from an A to G substitution at nucleotide position 383. The asparagine at codon 128 is replaced by serine, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Cardiac arrhythmia

Uncertain:1

Feb 14, 2024

Color Diagnostics, LLC DBA Color Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces asparagine with serine at codon 128 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 KCNH2-related disorders in the literature. This variant has been identified in 2/251450 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.29

CardioboostArm

Benign

0.00022

BayesDel_addAF

Benign

-0.032

BayesDel_noAF

Benign

-0.10

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.83

D;D

Eigen

Benign

-0.16

Eigen_PC

Benign

0.042

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.97

D;D

M_CAP

Pathogenic

0.35

MetaRNN

Uncertain

0.68

D;D

MetaSVM

Pathogenic

0.87

MutationAssessor

Benign

0.28

N;.

PhyloP100

7.5

PrimateAI

Uncertain

0.70

PROVEAN

Uncertain

-3.2

D;.

REVEL

Uncertain

0.49

Sift

Benign

0.069

T;.

Sift4G

Benign

0.23

T;T

Polyphen

0.0020

B;.

Vest4

0.81

MVP

0.84

MPC

0.82

ClinPred

0.39

GERP RS

4.7

Varity_R

0.45

gMVP

0.96

Mutation Taster

=30/70

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.11

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over