rs1220897906

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2PP2BP4

The NM_000238.4(KCNH2):​c.778G>C​(p.Ala260Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000367 in 1,363,138 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A260V) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000033 ( 0 hom. )

Consequence

KCNH2
NM_000238.4 missense

Scores

3
5
12

Clinical Significance

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

Conservation

PhyloP100: 0.349

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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
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.
BP4
Computational evidence support a benign effect (MetaRNN=0.3724612).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
KCNH2NM_000238.4 linkc.778G>C p.Ala260Pro 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.778G>C p.Ala260Pro missense_variant Exon 4 of 15 1 NM_000238.4 ENSP00000262186.5 Q12809-1

Frequencies

GnomAD3 genomes
AF:
0.00000659
AC:
1
AN:
151842
Hom.:
0
Cov.:
33
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:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD4 exome
AF:
0.00000330
AC:
4
AN:
1211296
Hom.:
0
Cov.:
32
AF XY:
0.00000170
AC XY:
1
AN XY:
589622
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
24416
American (AMR)
AF:
0.00
AC:
0
AN:
15146
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
18692
East Asian (EAS)
AF:
0.00
AC:
0
AN:
26548
South Asian (SAS)
AF:
0.00
AC:
0
AN:
51436
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
29534
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
3480
European-Non Finnish (NFE)
AF:
0.00000202
AC:
2
AN:
992482
Other (OTH)
AF:
0.0000404
AC:
2
AN:
49562
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.488
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.00000659
AC:
1
AN:
151842
Hom.:
0
Cov.:
33
AF XY:
0.0000135
AC XY:
1
AN XY:
74180
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
41406
American (AMR)
AF:
0.00
AC:
0
AN:
15236
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5178
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10494
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
314
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
67914
Other (OTH)
AF:
0.00
AC:
0
AN:
2084
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.375
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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:
0.00
Hom.:
0
Bravo
AF:
0.00000756

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
Jan 06, 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 proline, which is neutral and non-polar, at codon 260 of the KCNH2 protein (p.Ala260Pro). 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: 427970). 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. -

Hypertrophic cardiomyopathy Uncertain:1
Apr 30, 2017
Center for Human Genetics, University of Leuven
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
0.089
CardioboostArm
Uncertain
0.54
BayesDel_addAF
Pathogenic
0.24
D
BayesDel_noAF
Uncertain
0.11
CADD
Uncertain
23
DANN
Uncertain
0.99
DEOGEN2
Benign
0.36
T;T
Eigen
Benign
-0.16
Eigen_PC
Benign
-0.28
FATHMM_MKL
Benign
0.15
N
LIST_S2
Benign
0.75
T;T
M_CAP
Pathogenic
0.97
D
MetaRNN
Benign
0.37
T;T
MetaSVM
Uncertain
0.51
D
MutationAssessor
Benign
1.0
L;.
PhyloP100
0.35
PrimateAI
Pathogenic
0.90
D
PROVEAN
Benign
-0.57
N;.
REVEL
Uncertain
0.55
Sift
Benign
0.13
T;.
Sift4G
Benign
0.34
T;T
Polyphen
0.99
D;.
Vest4
0.16
MutPred
0.37
Gain of relative solvent accessibility (P = 0.0249);.;
MVP
0.95
MPC
1.8
ClinPred
0.52
D
GERP RS
3.6
Varity_R
0.13
gMVP
0.56
Mutation Taster
=81/19
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.040
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs1220897906; hg19: chr7-150655285; API