chr11-2445483-G-A

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM1PP2

The NM_000218.3(KCNQ1):c.385G>A(p.Val129Ile) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.0000069 in 1,594,412 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predict no significant impact on normal splicing. 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. V129G) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000035 ( 0 hom. )

Consequence

KCNQ1
NM_000218.3 missense, splice_region

Scores

Splicing: ADA: 0.5535

Clinical Significance

Uncertain significance criteria provided, single submitter U:1O:1

Conservation

PhyloP100: 5.73

Publications

7 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 Gene-Disease associations (from GenCC):

long QT syndrome
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
long QT syndrome 1
Inheritance: AD, AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
Jervell and Lange-Nielsen syndrome
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
Jervell and Lange-Nielsen syndrome 1
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), G2P
atrial fibrillation, familial, 3
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
short QT syndrome
Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet
short QT syndrome type 2
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
familial atrial fibrillation
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Jervell and Lange-Nielsen syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
hypertrophic cardiomyopathy
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

KCNQ1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM1

In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_000218.3

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 212 curated pathogenic missense variants (we use a threshold of 10). The gene has 12 curated benign missense variants. Gene score misZ: 1.8321 (below the threshold of 3.09). Trascript score misZ: 0.90233 (below the threshold of 3.09). GenCC associations: The gene is linked to short QT syndrome type 2, long QT syndrome 1, Jervell and Lange-Nielsen syndrome 1, long QT syndrome, short QT syndrome, Jervell and Lange-Nielsen syndrome, hypertrophic cardiomyopathy, familial atrial fibrillation, atrial fibrillation, familial, 3.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000218.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNQ1	NM_000218.3	MANE Select	c.385G>A	p.Val129Ile	missense splice_region	Exon 1 of 16	NP_000209.2
KCNQ1	NM_001406836.1		c.385G>A	p.Val129Ile	missense splice_region	Exon 1 of 15	NP_001393765.1
KCNQ1	NM_001406837.1		c.23G>A	p.Arg8His	missense splice_region	Exon 1 of 17	NP_001393766.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNQ1	ENST00000155840.12	TSL:1 MANE Select	c.385G>A	p.Val129Ile	missense splice_region	Exon 1 of 16	ENSP00000155840.2
KCNQ1	ENST00000345015.4	TSL:1	n.162G>A		splice_region non_coding_transcript_exon	Exon 1 of 3
KCNQ1	ENST00000713725.1		c.385G>A	p.Val129Ile	missense splice_region	Exon 1 of 15	ENSP00000519029.1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152226

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000145

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000187

AC:

AN:

214296

AF XY:

0.0000251

show subpopulations

Gnomad AFR exome

AF:

0.000155

Gnomad AMR exome

AF:

0.0000300

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000104

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000347

AC:

AN:

1442186

Hom.:

Cov.:

AF XY:

0.00000418

AC XY:

AN XY:

717520

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000598

AC:

AN:

33450

American (AMR)

AF:

0.0000226

AC:

AN:

44336

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26018

East Asian (EAS)

AF:

0.00

AC:

AN:

39568

South Asian (SAS)

AF:

0.0000117

AC:

AN:

85622

European-Finnish (FIN)

AF:

0.00

AC:

AN:

36872

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5708

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1110562

Other (OTH)

AF:

0.00

AC:

AN:

60050

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000224764), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.365

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:

0.0000394

AC:

AN:

152226

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74366

show subpopulations

African (AFR)

AF:

0.000145

AC:

AN:

41480

American (AMR)

AF:

0.00

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5170

South Asian (SAS)

AF:

0.00

AC:

AN:

4838

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68030

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.533

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.000172

Hom.:

Bravo

AF:

0.0000529

ExAC

AF:

0.00000854

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1Other:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Long QT syndrome

Uncertain:1

Apr 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 129 of the KCNQ1 protein (p.Val129Ile). 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 KCNQ1-related conditions. ClinVar contains an entry for this variant (Variation ID: 67068). 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. Experimental studies have shown that this missense change does not substantially affect KCNQ1 function (PMID: 29532034, 30571187). This variant disrupts the p.Val129 amino acid residue in KCNQ1. Other variant(s) that disrupt this residue have been observed in individuals with KCNQ1-related conditions (PMID: 27920829; Invitae), which suggests that this may be a clinically significant amino acid residue. 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.

not provided

Other:1

Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

This variant has been reported in the following publications (PMID:14661677;PMID:19841300).

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.44

CardioboostArm

Benign

0.10

BayesDel_addAF

Pathogenic

0.21

BayesDel_noAF

Uncertain

0.060

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.71

Eigen

Uncertain

0.35

Eigen_PC

Uncertain

0.34

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.86

M_CAP

Uncertain

0.18

MetaRNN

Uncertain

0.50

MetaSVM

Uncertain

0.73

MutationAssessor

Benign

2.0

PhyloP100

5.7

PrimateAI

Uncertain

0.65

PROVEAN

Benign

-0.71

REVEL

Uncertain

0.60

Sift

Benign

0.078

Sift4G

Benign

0.12

Polyphen

0.88

Vest4

0.33

MutPred

0.63

Loss of catalytic residue at V129 (P = 0.021)

MVP

0.94

MPC

1.3

ClinPred

0.36

GERP RS

3.2

PromoterAI

0.015

Neutral

(source)

Varity_R

0.27

gMVP

0.83

Mutation Taster

=32/68

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.55

dbscSNV1_RF

Benign

0.54

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over