NM_000218.3:c.1355G>T

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM5

The NM_000218.3(KCNQ1):c.1355G>T(p.Arg452Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000496 in 1,613,016 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R452Q) has been classified as Likely pathogenic.

Frequency

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

Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

KCNQ1
NM_000218.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:3

Conservation

PhyloP100: 1.59

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM5

Other missense variant is known to change same aminoacid residue: Variant chr11-2588816-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ1	NM_000218.3 link	c.1355G>T	p.Arg452Leu	missense_variant	Exon 10 of 16	ENST00000155840.12	NP_000209.2	P51787-1Q96AI9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
KCNQ1	ENST00000155840.12 link	c.1355G>T	p.Arg452Leu	missense_variant	Exon 10 of 16	1	NM_000218.3	ENSP00000155840.2	P51787-1
KCNQ1	ENST00000335475.6 link	c.974G>T	p.Arg325Leu	missense_variant	Exon 10 of 16	1		ENSP00000334497.5	P51787-2
KCNQ1	ENST00000496887.7 link	c.998G>T	p.Arg333Leu	missense_variant	Exon 10 of 16	5		ENSP00000434560.2	E9PPZ0
KCNQ1	ENST00000646564.2 link	c.815G>T	p.Arg272Leu	missense_variant	Exon 5 of 11			ENSP00000495806.2	A0A2R8YEQ9

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152138

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:

0.00

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

GnomAD3 exomes

AF:

0.00000801

AC:

AN:

249712

Hom.:

AF XY:

0.00000739

AC XY:

AN XY:

135286

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:

0.00000887

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.00000479

AC:

AN:

1460878

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726714

show subpopulations

Gnomad4 AFR exome

AF:

0.00

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:

0.00000540

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152138

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74310

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Long QT syndrome

Uncertain:2

Nov 11, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with KCNQ1-related conditions. ClinVar contains an entry for this variant (Variation ID: 200904). This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with leucine at codon 452 of the KCNQ1 protein (p.Arg452Leu). The arginine residue is weakly conserved and there is a moderate physicochemical difference between arginine and leucine. -

Apr 16, 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 arginine with leucine at codon 452 of the KCNQ1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). A functional study has shown that this variant causes a reduction of channel current in transfected HEK293 cells (PMID: 34930020). This variant has been reported in an individual affected with premature ventricular contraction (PMID: 34930020). This variant has been identified in 2/249712 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. -

not provided

Pathogenic:1

Jan 09, 2012

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense change is denoted Arg452Leu (aka R452L) at the protein level and c.1355 G>T at the cDNA level. The Arg452Leu mutation has not been reported previously as a disease-causing mutation or as a benign polymorphism, to our knowledge. Another mutation at this codon (Arg452Trp) has been published as a disease-causing mutation in one individual with LQTS and it was absent from 1,500 reference alleles ( Tester D et al., 2005). Arg452Leu results in a non-conservative amino acid substitution of a positively charged Arginine residue with a non-polar Leucine residue. Other mutations in nearby codons (Arg451Gln, Arg451Trp, His455Tyr) have been reported in association with LQTS, further supporting the functional importance of this region of the protein. Additionally, the NHLBI ESP Exome Variant Server reports Arg452Leu was not observed in approximately 5,300 samples from individuals of European and African American backgrounds, indicating it is not a common benign variant in these populations.The variant is found in LQT panel(s). -

Cardiovascular phenotype

Uncertain:1

Oct 26, 2020

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R452L variant (also known as c.1355G>T), located in coding exon 10 of the KCNQ1 gene, results from a G to T substitution at nucleotide position 1355. The arginine at codon 452 is replaced by leucine, an amino acid with dissimilar properties, and is located in the cytoplasmic C-terminal region. This amino acid position is not 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Pathogenic

0.25

BayesDel_noAF

Uncertain

0.13

CADD

Benign

DANN

Benign

0.89

DEOGEN2

Uncertain

0.62

D;.;.

Eigen

Benign

-0.71

Eigen_PC

Benign

-0.71

FATHMM_MKL

Benign

0.25

LIST_S2

Benign

0.79

T;T;T

M_CAP

Pathogenic

0.42

MetaRNN

Uncertain

0.66

D;D;D

MetaSVM

Pathogenic

0.91

MutationAssessor

Benign

1.4

L;.;.

PrimateAI

Benign

0.36

PROVEAN

Benign

-2.0

N;.;N

REVEL

Uncertain

0.60

Sift

Benign

0.24

T;.;T

Sift4G

Benign

0.26

T;.;T

Polyphen

0.016

B;.;B

Vest4

0.46

MutPred

0.64

Loss of solvent accessibility (P = 0.0606);.;.;

MVP

0.93

MPC

0.90

ClinPred

0.62

GERP RS

2.5

Varity_R

0.17

gMVP

0.48

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.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over