NM_000218.3:c.1926C>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_ModeratePM2

The NM_000218.3(KCNQ1):​c.1926C>A​(p.Cys642*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. C642C) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 0.0 ( 0 hom. )
Failed GnomAD Quality Control

Consequence

KCNQ1
NM_000218.3 stop_gained

Scores

4
10

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -2.52

Publications

2 publications found
Variant links:
Genes affected
KCNQ1 (HGNC:6294): (potassium voltage-gated channel subfamily Q member 1) This gene encodes a voltage-gated potassium channel required for repolarization phase of the cardiac action potential. This protein can form heteromultimers with two other potassium channel proteins, KCNE1 and KCNE3. Mutations in this gene are associated with hereditary long QT syndrome 1 (also known as Romano-Ward syndrome), Jervell and Lange-Nielsen syndrome, and familial atrial fibrillation. This gene exhibits tissue-specific imprinting, with preferential expression from the maternal allele in some tissues, and biallelic expression in others. This gene is located in a region of chromosome 11 amongst other imprinted genes that are associated with Beckwith-Wiedemann syndrome (BWS), and itself has been shown to be disrupted by chromosomal rearrangements in patients with BWS. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Aug 2011]
KCNQ1-AS1 (HGNC:42790): (KCNQ1 antisense RNA 1)

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0517 CDS is truncated, and there are 1 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
KCNQ1NM_000218.3 linkc.1926C>A p.Cys642* stop_gained Exon 16 of 16 ENST00000155840.12 NP_000209.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
KCNQ1ENST00000155840.12 linkc.1926C>A p.Cys642* stop_gained Exon 16 of 16 1 NM_000218.3 ENSP00000155840.2

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD4 exome
Data not reliable, filtered out with message: AC0
AF:
0.00
AC:
0
AN:
1427406
Hom.:
0
Cov.:
31
AF XY:
0.00
AC XY:
0
AN XY:
706886
African (AFR)
AF:
0.00
AC:
0
AN:
32688
American (AMR)
AF:
0.00
AC:
0
AN:
40778
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25454
East Asian (EAS)
AF:
0.00
AC:
0
AN:
37634
South Asian (SAS)
AF:
0.00
AC:
0
AN:
81880
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
49306
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5716
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1094986
Other (OTH)
AF:
0.00
AC:
0
AN:
58964
GnomAD4 genome
Cov.:
33

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Cardiac arrhythmia Uncertain:1
Oct 22, 2019
Color Diagnostics, LLC DBA Color Health
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant changes 1 nucleotide in exon 16 of the KCNQ1 gene, creating a premature translation stop signal in the last coding exon. This variant is expected to escape nonsense-mediated decay and expressed as a truncated protein product missing the last 35 amino acids of the KCNQ1 protein. The truncated region is not part of any known functional domains of the KCNQ1 protein. To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has not been identified 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
BayesDel_addAF
Pathogenic
0.34
D
BayesDel_noAF
Pathogenic
0.25
CADD
Pathogenic
29
DANN
Benign
0.96
DEOGEN2
Benign
0.0
.;.;.
Eigen
Benign
-0.12
Eigen_PC
Benign
-0.59
FATHMM_MKL
Benign
0.046
N
LIST_S2
Benign
0.0
.;.;.
MetaRNN
Benign
0.0
.;.;.
MutationAssessor
Benign
0.0
.;.;.
PhyloP100
-2.5
PROVEAN
Benign
0.0
.;.;.
REVEL
Benign
0.0
Sift
Pathogenic
0.0
.;.;.
Sift4G
Pathogenic
0.0
.;.;.
Vest4
0.70
GERP RS
-0.79
Mutation Taster
=66/134
disease causing

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

Other links and lift over

dbSNP: rs12720454; hg19: chr11-2869128; API