rs199472745

Positions:

• chr11-2583441-G-A

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.928G>A​(p.Val310Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,460,318 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. V310D) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:4 O:1
• Conservation: PhyloP100: 6.23

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 13 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 chr11-2583442-T-A is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.904
• PP5: Variant 11-2583441-G-A is Pathogenic according to our data. Variant chr11-2583441-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 53133.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-2583441-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ1	NM_000218.3	c.928G>A	p.Val310Ile	missense_variant	7/16	ENST00000155840.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ1	ENST00000155840.12	c.928G>A	p.Val310Ile	missense_variant	7/16	1	NM_000218.3	P1
KCNQ1	ENST00000335475.6	c.547G>A	p.Val183Ile	missense_variant	7/16	1
KCNQ1	ENST00000496887.7	c.667G>A	p.Val223Ile	missense_variant	8/16	5
KCNQ1	ENST00000646564.2	c.484G>A	p.Val162Ile	missense_variant	3/11

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460318 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726540

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:4 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Aug 16, 2023	This variant has been reported in multiple individuals with Long QT syndrome (PMID: 10973849, 17470695, 19490272, 26318259, 29033053, 27041150, 31565860). This variant is located in a well-established functional domain of the protein where other pathogenic or likely pathogenic variants have been described (PMID: 32893267). This variant is absent from large population databases, including the Genome Aggregation Database (http://gnomad.broadinstitute.org/). This variant is predicted to be deleterious by in silico analysis. Functional studies suggest that this variant results in a deleterious effect on the protein (PMID: 32893267, 15649981). -
Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Nov 29, 2022	In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Experimental studies have shown that this missense change affects KCNQ1 function (PMID: 15051636, 15649981, 24912595). 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. ClinVar contains an entry for this variant (Variation ID: 53133). This missense change has been observed in individuals with long QT syndrome (PMID: 15051636, 19490272). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 310 of the KCNQ1 protein (p.Val310Ile). -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jul 28, 2017

The V310I likely pathogenic variant in the KCNQ1 gene has been reported in several individuals with LQTS (Splawski et al., 2000; Moss et al., 2007), though detailed clinical and segregation information were not provided. Additionally, this variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). Though the V310I variant is a conservative amino acid substitution, it occurs at a position that is conserved across species, and in silico analysis suggests that this variant is probably damaging to the protein structure/function. Furthermore, functional studies show that the V310I pathogenic variant results in partial loss of potassium channel function (Westenskow et al., 2004; Seebohm et al., 2005). Finally, multiple missense variants in nearby residues (W305S, W305L, G306R, V307M, T312I, G314S, Y315C, Y315S) are independently classified as likely pathogenic/pathogenic by GeneDx. -

Cardiac arrhythmia Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Sep 20, 2023

This missense variant replaces valine with isoleucine at codon 310 in the KCNQ1 protein. This variant is found within the highly conserved pore-forming domain (a.a. 300-320). Rare non-truncating variants in this region have been shown to be significantly overrepresented in individuals with long QT syndrome (PMID: 32893267) Functional studies have shown that this variant moderately affects channel trafficking by retention of the mutant protein in the endoplasmic reticulum (PMID: 24912595) and causes a reduction in potassium channel current (PMID: 15051636, 15649981). This variant has been reported in several individuals affected long QT syndrome (PMID: 10973849, 15051636 , 17470695, 19490272, 24912595, 26318259). In two of these individuals, this variant was observed in compound heterozygous state with a known pathogenic KCNQ1 variant (PMID: 15051636 , 24912595). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). 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:10973849;PMID:15051636;PMID:17470695;PMID:15649981). 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	0.29
BayesDel_addAF	Pathogenic	0.48	D
BayesDel_noAF	Pathogenic	0.45
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.65	D;.;.
Eigen	Uncertain	0.38
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Uncertain	0.77	D
LIST_S2	Uncertain	0.96	D;D;D
M_CAP	Pathogenic	0.56	D
MetaRNN	Pathogenic	0.90	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Benign	0.28	N;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-0.60	N;.;N
REVEL	Pathogenic	0.78
Sift	Uncertain	0.0050	D;.;D
Sift4G	Uncertain	0.042	D;.;D
Polyphen		0.89	P;.;D
Vest4		0.85
MutPred		0.81		Loss of helix (P = 0.0376);.;.;
MVP		0.96
MPC		1.0
ClinPred		0.91	D
GERP RS		3.9
Varity_R		0.58
gMVP		0.93

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: rs199472745; hg19: chr11-2604671;