Genetic Variant KCNH2:p.Arg252Arg (chr7-150958221-G-T) – ACMG Classification: Benign (-11 pts)

Variant summary

Our verdict is Benign. The variant received -11 ACMG points: 2P and 13B. PM2BP4_StrongBP6_Very_StrongBP7

The NM_000238.4(KCNH2):c.754C>A(p.Arg252Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000219 in 1,371,692 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. R252R) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 8.2e-7 ( 0 hom. )

Consequence

KCNH2
NM_000238.4 synonymous

Scores

Clinical Significance

Likely benign criteria provided, multiple submitters, no conflicts B:3

Conservation

PhyloP100: 1.14

Publications

4 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: Benign. The variant received -11 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.75).

BP6

Variant 7-150958221-G-T is Benign according to our data. Variant chr7-150958221-G-T is described in ClinVar as Likely_benign. ClinVar VariationId is 1203189.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=1.14 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000238.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNH2	NM_000238.4	MANE Select	c.754C>A	p.Arg252Arg	synonymous	Exon 4 of 15	NP_000229.1
KCNH2	NM_001406753.1		c.466C>A	p.Arg156Arg	synonymous	Exon 2 of 13	NP_001393682.1
KCNH2	NM_172056.3		c.754C>A	p.Arg252Arg	synonymous	Exon 4 of 9	NP_742053.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNH2	ENST00000262186.10	TSL:1 MANE Select	c.754C>A	p.Arg252Arg	synonymous	Exon 4 of 15	ENSP00000262186.5
KCNH2	ENST00000713710.1		c.754C>A	p.Arg252Arg	synonymous	Exon 4 of 15	ENSP00000519013.1
KCNH2	ENST00000713701.1		c.454C>A	p.Arg152Arg	synonymous	Exon 3 of 14	ENSP00000519004.1

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

151846

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000385

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:

8.20e-7

AC:

AN:

1219738

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

594704

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

24680

American (AMR)

AF:

0.00

AC:

AN:

15396

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

18662

East Asian (EAS)

AF:

0.0000374

AC:

AN:

26756

South Asian (SAS)

AF:

0.00

AC:

AN:

53040

European-Finnish (FIN)

AF:

0.00

AC:

AN:

29940

Middle Eastern (MID)

AF:

0.00

AC:

AN:

3550

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

997778

Other (OTH)

AF:

0.00

AC:

AN:

49936

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

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:

0.0000132

AC:

AN:

151954

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74300

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41514

American (AMR)

AF:

0.00

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000387

AC:

AN:

5174

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10492

Middle Eastern (MID)

AF:

0.00

AC:

AN:

292

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67906

Other (OTH)

AF:

0.00

AC:

AN:

2108

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000189

ClinVar

Significance: Likely benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:1

Dec 09, 2019

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Long QT syndrome

Benign:1

Jan 30, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Cardiovascular phenotype

Benign:1

Jun 17, 2024

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.75

CADD

Benign

6.9

(source)

DANN

Benign

0.87

PhyloP100

1.1

Mutation Taster

=100/0

polymorphism

(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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over