rs199472804

Positions:

• chr11-2776997-C-A
• chr11-2776997-C-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_000218.3(KCNQ1):​c.1697C>A​(p.Ser566Tyr) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,820 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S566P) 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: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 4.48

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 hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 14 uncertain in NM_000218.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr11-2776997-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 53006.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.9
• PP5: Variant 11-2776997-C-A is Pathogenic according to our data. Variant chr11-2776997-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 53005.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-2776997-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ1	NM_000218.3	c.1697C>A	p.Ser566Tyr	missense_variant	14/16	ENST00000155840.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ1	ENST00000155840.12	c.1697C>A	p.Ser566Tyr	missense_variant	14/16	1	NM_000218.3	P1
KCNQ1	ENST00000335475.6	c.1316C>A	p.Ser439Tyr	missense_variant	14/16	1
KCNQ1	ENST00000496887.7	c.1340C>A	p.Ser447Tyr	missense_variant	14/16	5
KCNQ1	ENST00000646564.2	c.1157C>A	p.Ser386Tyr	missense_variant	9/11

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461820 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727212

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

Bravo AF: 0.00000378

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

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jul 10, 2020

Variant found to segregate with disease in two affected relatives of a patient with LQTS tested at GeneDx; Reported in ClinVar (ClinVar Variant ID# 53005; Landrum et al., 2016); 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: 19716085, 15840476, 23631430, 19862833, 28606196, 31415974, 32421437, 22949429) -

Long QT syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Dec 22, 2023

This sequence change replaces serine, which is neutral and polar, with tyrosine, which is neutral and polar, at codon 566 of the KCNQ1 protein (p.Ser566Tyr). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with clinical features of autosomal dominant long QT syndrome (PMID: 15840476, 19716085, 23631430, 28606196, 32421437; Invitae). ClinVar contains an entry for this variant (Variation ID: 53005). 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%. This variant disrupts the p.Ser566 amino acid residue in KCNQ1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10973849, 22949429). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Cardiac arrhythmia Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Mar 13, 2023

This missense variant replaces serine with tyrosine at codon 566 of the KCNQ1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). This variant is found within a highly conserved region of the C-terminal cytoplasmic domain. Rare nontruncating variants in this region have been shown to be significantly overrepresented in individuals with long QT syndrome (PMID: 32893267). This variant has been reported in ten individuals from four families affected with long QT syndrome (PMID: 31415974, 32421437, ClinVar SCV000074027.7, SCV000234518.8), another three unrelated individuals suspected of having long QT syndrome (PMID: 15840476, 19716085), and an individual affected with syncope (PMID: 28606196). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). A different missense variant occurring at the same codon, p.Ser566Phe, is considered to be disease causing (ClinVar variation ID 53006), indicating that serine at this position is important for KCNQ1 protein function. Based on the available evidence, this variant is classified as Likely Pathogenic. -

Congenital long QT syndrome 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 Long QT syndrome in the following publications (PMID:15840476;PMID:19716085). 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	0.91
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.94	D;.;.
Eigen	Uncertain	0.47
Eigen_PC	Uncertain	0.45
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Pathogenic	0.82	D
MetaRNN	Pathogenic	0.90	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.3	M;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.73	T
PROVEAN	Uncertain	-3.1	D;.;D
REVEL	Pathogenic	0.84
Sift	Uncertain	0.0070	D;.;D
Sift4G	Uncertain	0.019	D;.;D
Polyphen		1.0	D;.;P
Vest4		0.96
MutPred		0.53		Loss of disorder (P = 0.0041);.;.;
MVP		0.97
MPC		1.3
ClinPred		0.97	D
GERP RS		4.0
Varity_R		0.80
gMVP		0.98

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: rs199472804; hg19: chr11-2798227;