rs199472689

chr11-2527981-A-Gchr11-2527981-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000218.3(KCNQ1):c.440A>G(p.Gln147Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,786 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q147L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: 7.54

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 6 uncertain in NM_000218.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.926

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ1	NM_000218.3	c.440A>G	p.Gln147Arg	missense_variant	2/16	ENST00000155840.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ1	ENST00000155840.12	c.440A>G	p.Gln147Arg	missense_variant	2/16	1	NM_000218.3	P1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251418 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135884

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461786 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727208

Gnomad4 AFR exome AF: 0.0000299

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

May 04, 2023

This missense variant replaces glutamine with arginine at codon 147 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). A functional study has shown that this variant causes a decrease in channel current when co-expressed with KCNE1, while upon co-expressed with KCNE2 it causes an increase in the current amplitude in heterologous expression systems (PMID: 17997361). This variant has been reported in an individual affected with atrial fibrillation and prolonged QT interval (PMID: 17997361). This variant has been identified in 1/251418 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Atrial fibrillation 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 Atrial fibrillation in the following publications (PMID:17997361). 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	0.10
CardioboostArm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.49
Cadd	Uncertain	25
Dann	Uncertain	1.0
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.76	T;T;D;T
M_CAP	Pathogenic	0.67	D
MetaRNN	Pathogenic	0.93	D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.65	T
PROVEAN	Benign	-2.1	N;N;.;N
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0010	D;D;.;D
Sift4G	Benign	0.082	T;T;.;D
Polyphen		0.93	.;P;.;.
Vest4		0.92, 0.82
MutPred		0.77		.;Loss of catalytic residue at Q147 (P = 0.0643);.;.;
MVP		0.97
MPC		2.1
ClinPred		0.93	D
GERP RS		4.5
Varity_R		0.79
gMVP		0.91

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs199472689; hg19: chr11-2549211;