rs199472734

Variant names:

• chr11-2572915-G-A
• rs199472734
• NM_000218.3:c.850G>A

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_000218.3(KCNQ1):​c.850G>A​(p.Glu284Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 9.36

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]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a helix (size 25) in uniprot entity KCNQ1_HUMAN there are 38 pathogenic changes around while only 0 benign (100%) in NM_000218.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.986
• PP5: Variant 11-2572915-G-A is Pathogenic according to our data. Variant chr11-2572915-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 67115.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-2572915-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.850G>A	p.Glu284Lys	missense_variant	Exon 6 of 16	ENST00000155840.12	NP_000209.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.850G>A	p.Glu284Lys	missense_variant	Exon 6 of 16	1	NM_000218.3	ENSP00000155840.2
KCNQ1	ENST00000335475.6	c.469G>A	p.Glu157Lys	missense_variant	Exon 6 of 16	1		ENSP00000334497.5
KCNQ1	ENST00000496887.7	c.589G>A	p.Glu197Lys	missense_variant	Exon 7 of 16	5		ENSP00000434560.2
KCNQ1	ENST00000646564.2	c.478-10520G>A		intron_variant	Intron 2 of 10			ENSP00000495806.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Aug 06, 2020

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 23631430, 14678125, 17470695, 19490272, 19862833, 19815527, 21185501, 22456477, 26669661, 28217227, 26318259, 20541041) -

Long QT syndrome Pathogenic:1

Apr 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 284 of the KCNQ1 protein (p.Glu284Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with long QT syndrome (PMID: 14678125, 17470695; Invitae). ClinVar contains an entry for this variant (Variation ID: 67115). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt KCNQ1 protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

Cardiovascular phenotype Pathogenic:1

Jan 17, 2023

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.E284K variant (also known as c.850G>A), located in coding exon 6 of the KCNQ1 gene, results from a G to A substitution at nucleotide position 850. The glutamic acid at codon 284 is replaced by lysine, an amino acid with similar properties, and is located in S5 pore region. This variant has been detected in individuals from long QT syndrome (LQTS) cohorts; however, details were limited (Zareba W et al. J. Cardiovasc Electrophysiol. 2003 Nov;14:1149-53; Moss AJ et al. Circulation. 2007 May;115:2481-9; Ozawa J et al. Circ J. 2018 08;82:2269-2276; Yee LA et al. J Am Heart Assoc. 2022 Sep;11(18):e025108; GeneDx pers. comm.). This variant co-occurred with a variant in SCN5A in two siblings, one of which was reportedly symptomatic with a QTc of 478ms while the other was asymptomatic with QTc 430ms (Itoh H et al. Heart Rhythm. 2010 Oct;7:1411-8). Based on internal structural analysis, this variant is predicted to be more disruptive than other known pathogenic variants (Sun J et al. Cell. 2017 Jun;169(6):1042-1050.e9). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Congenital long QT syndrome 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 as associated with Long QT syndrome in the following publications (PMID:14678125;PMID:17470695). This is a literature report, and does not necessarily reflect the clinical interpretation of the Imperial College / Royal Brompton Cardiovascular Genetics laboratory. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.99	D;.
Eigen	Pathogenic	0.72
Eigen_PC	Uncertain	0.58
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D;D
M_CAP	Pathogenic	0.96	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.9	H;.
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-3.9	D;D
REVEL	Pathogenic	0.98
Sift	Uncertain	0.0010	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.99
MutPred		0.87		Gain of ubiquitination at E284 (P = 0.0258);.;
MVP		0.98
MPC		1.2
ClinPred		1.0	D
GERP RS		3.7
Varity_R		0.99
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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

Other links and lift over

dbSNP: rs199472734; hg19: chr11-2594145;