rs36210419

chr11-2571372-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000218.3(KCNQ1):c.652A>G(p.Lys218Glu) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,460,726 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. K218R) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3 O:1
• Conservation: PhyloP100: 5.80

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 Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_000218.3
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ1	NM_000218.3	c.652A>G	p.Lys218Glu	missense_variant	4/16	ENST00000155840.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ1	ENST00000155840.12	c.652A>G	p.Lys218Glu	missense_variant	4/16	1	NM_000218.3	P1
KCNQ1	ENST00000335475.6	c.271A>G	p.Lys91Glu	missense_variant	4/16	1
KCNQ1	ENST00000496887.7	c.391A>G	p.Lys131Glu	missense_variant	5/16	5
KCNQ1	ENST00000646564.2	c.478-12063A>G		intron_variant

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460726 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726722

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Nov 06, 2017

The K218E variant in the KCNQ1 gene has been reported one individual with torsades de pointes, however no clinical or segregation information was provided (Mank-Seymore et al., 2006). The K218E variant is not observed in large population cohorts (Lek et al., 2016). The K218E variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position conserved in mammals. A majority of in silico analysis predicts this variant is probably damaging to the protein structure/function. Thus, this variant lacks observation in a significant number of affected individuals, segregation data, and functional evidence, which would further clarify its pathogenicity. -

Long QT syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 14, 2021

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. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on KCNQ1 protein function (PMID: 29532034, 30571187). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. ClinVar contains an entry for this variant (Variation ID: 67095). This variant has been observed in individual(s) with torsades de pointes (PMID: 17161064). This variant is not present in population databases (ExAC no frequency). This sequence change replaces lysine with glutamic acid at codon 218 of the KCNQ1 protein (p.Lys218Glu). The lysine residue is moderately conserved and there is a small physicochemical difference between lysine and glutamic acid. -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 15, 2018

The c.652A>G (p.K218E) alteration is located in exon 4 (coding exon 4) of the KCNQ1 gene. This alteration results from a A to G substitution at nucleotide position 652, causing the lysine (K) at amino acid position 218 to be replaced by a glutamic acid (E). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Torsades de pointes Other:1

not provided, no classification provided

literature only

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

-

This variant has been reported as associated with torsades de pointes in the following publications (PMID:17161064). 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	Benign	0.14
CardioboostArm	Benign	0.0072
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.23
Cadd	Uncertain	25
Dann	Uncertain	1.0
Eigen	Benign	-0.26
Eigen_PC	Benign	-0.066
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Uncertain	0.28	D
MetaRNN	Uncertain	0.52	D;D;D
MetaSVM	Uncertain	0.53	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.70	T
PROVEAN	Benign	-0.69	N;N;N
REVEL	Uncertain	0.58
Sift	Benign	0.089	T;T;T
Sift4G	Benign	0.35	T;T;T
Polyphen		0.070	.;B;.
Vest4		0.66, 0.65
MutPred		0.63		.;Loss of ubiquitination at K218 (P = 0.0224);.;
MVP		0.93
MPC		0.58
ClinPred		0.79	D
GERP RS		4.3
Varity_R		0.44
gMVP		0.90

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

Other links and lift over

dbSNP: rs36210419; hg19: chr11-2592602;