rs199472872

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_ModerateBS2

The NM_000238.4(KCNH2):​c.724C>T​(p.Arg242Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000989 in 1,415,168 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000079 ( 1 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

1
3
15

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: -1.24
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -6 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.20563468).
BS2
High AC in GnomAdExome4 at 10 AD,Digenic gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
KCNH2NM_000238.4 linkc.724C>T p.Arg242Cys missense_variant Exon 4 of 15 ENST00000262186.10 NP_000229.1 Q12809-1Q15BH2A0A090N8Q0

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
KCNH2ENST00000262186.10 linkc.724C>T p.Arg242Cys missense_variant Exon 4 of 15 1 NM_000238.4 ENSP00000262186.5 Q12809-1
KCNH2ENST00000532957.5 linkn.947C>T non_coding_transcript_exon_variant Exon 4 of 9 2
KCNH2ENST00000684241.1 linkn.1557C>T non_coding_transcript_exon_variant Exon 2 of 13

Frequencies

GnomAD3 genomes
AF:
0.0000263
AC:
4
AN:
151820
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000657
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:
0.0000442
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.0000179
AC:
1
AN:
55836
Hom.:
0
AF XY:
0.0000305
AC XY:
1
AN XY:
32772
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000465
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000792
AC:
10
AN:
1263348
Hom.:
1
Cov.:
32
AF XY:
0.00000806
AC XY:
5
AN XY:
620438
show subpopulations
Gnomad4 AFR exome
AF:
0.0000390
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:
0.00000882
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
AF:
0.0000263
AC:
4
AN:
151820
Hom.:
0
Cov.:
33
AF XY:
0.0000135
AC XY:
1
AN XY:
74168
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.0000657
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000442
Gnomad4 OTH
AF:
0.00
Bravo
AF:
0.0000151

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Long QT syndrome Uncertain:1
Oct 18, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 242 of the KCNH2 protein (p.Arg242Cys). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. 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: 652662). 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. -

Cardiovascular phenotype Uncertain:1
Mar 04, 2025
Ambry Genetics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The p.R242C variant (also known as c.724C>T), located in coding exon 4 of the KCNH2 gene, results from a C to T substitution at nucleotide position 724. The arginine at codon 242 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.089
BayesDel_addAF
Uncertain
0.029
T
BayesDel_noAF
Benign
-0.20
CADD
Benign
9.3
DANN
Benign
0.90
DEOGEN2
Benign
0.35
T;T
Eigen
Benign
-1.4
Eigen_PC
Benign
-1.4
FATHMM_MKL
Benign
0.041
N
LIST_S2
Benign
0.40
T;T
M_CAP
Pathogenic
0.83
D
MetaRNN
Benign
0.21
T;T
MetaSVM
Uncertain
0.26
D
MutationAssessor
Benign
0.0
N;.
PrimateAI
Uncertain
0.78
T
PROVEAN
Benign
0.060
N;.
REVEL
Benign
0.25
Sift
Benign
0.19
T;.
Sift4G
Benign
0.064
T;T
Polyphen
0.20
B;.
Vest4
0.16
MutPred
0.41
Loss of solvent accessibility (P = 0.0079);.;
MVP
0.69
MPC
1.5
ClinPred
0.18
T
GERP RS
-1.9
Varity_R
0.057
gMVP
0.42

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.

Other links and lift over

dbSNP: rs199472872; hg19: chr7-150655339; API