rs199472806

chr11-2777003-G-C

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_000218.3(KCNQ1):c.1703G>C(p.Gly568Ala) 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. 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. G568R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2 O:1
• Conservation: PhyloP100: 7.70

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 12 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 12 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 chr11-2777002-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 53009.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 11-2777003-G-C is Pathogenic according to our data. Variant chr11-2777003-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 53010.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr11-2777003-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ1	NM_000218.3	c.1703G>C	p.Gly568Ala	missense_variant	14/16	ENST00000155840.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ1	ENST00000155840.12	c.1703G>C	p.Gly568Ala	missense_variant	14/16	1	NM_000218.3	P1
KCNQ1	ENST00000335475.6	c.1322G>C	p.Gly441Ala	missense_variant	14/16	1
KCNQ1	ENST00000496887.7	c.1346G>C	p.Gly449Ala	missense_variant	14/16	5
KCNQ1	ENST00000646564.2	c.1163G>C	p.Gly388Ala	missense_variant	9/11

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome 1 Pathogenic:1

Pathogenic, no assertion criteria provided

research

Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital

Jan 01, 2012

- -

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 08, 2017

The p.G568A variant (also known as c.1703G>C), located in coding exon 14 of the KCNQ1 gene, results from a G to C substitution at nucleotide position 1703. The glycine at codon 568 is replaced by alanine, an amino acid with similar properties. This alteration has been reported in individuals with long QT syndrome, including one family with an affected mother and child (Chen S et al. Clin. Genet., 2003 Apr;63:273-82; Vyas B et al. Indian Pacing Electrophysiol J , 2016 Mar;16:8-18). Alternate amino acid substitutions, p.G568R and p.G568E, have also been reported in individuals with LQTS (Tester DJ et al. Heart Rhythm, 2005 May;2:507-17; Izumi G et al. Pediatr Cardiol, 2016 Jun;37:962-70). 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

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:12702160). 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	0.96
CardioboostArm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
Cadd	Pathogenic	27
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;.;.
Eigen	Pathogenic	0.73
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.93	D;D;D
M_CAP	Pathogenic	0.71	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	0.86	D
MutationAssessor	Uncertain	2.3	M;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.73	T
PROVEAN	Pathogenic	-5.3	D;.;D
REVEL	Pathogenic	0.94
Sift	Uncertain	0.0020	D;.;D
Sift4G	Pathogenic	0.0	D;.;D
Polyphen		0.99	D;.;D
Vest4		0.87
MutPred		0.96		Loss of stability (P = 0.0302);.;.;
MVP		0.97
MPC		1.2
ClinPred		1.0	D
GERP RS		4.0
Varity_R		0.90
gMVP		0.99

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: rs199472806; hg19: chr11-2798233;