NM_000218.3:c.590C>T

Variant names:

• chr11-2570740-C-T
• rs200108320
• NM_000218.3:c.590C>T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP3

This summary comes from the ClinGen Evidence Repository: NM_000218.3(KCNQ1):c.590C>T is a missense variant predicted to cause replacement of proline with leucine at position 197. This residue is conserved across the 5 human KCNQ paralogues (https://www.cardiodb.org/paralogue_annotation/gene.php?name=KCNQ1) and another missense variant in the same codon, NM_000218.3(KCNQ1):c.589C>T (p.Pro197Ser), has been investigated in connection with long QT syndrome 1 (PMID:29532034) but has been classified as a variant of uncertain significance for long QT syndrome 1 by the ClinGen Potassium Channel Arrhythmia VCEP, so PM5 is not yet met. This variant is present in gnomAD v.4.1.0 at a maximum allele frequency of 0.00004576, with 54 / 1179994 in the European non-FInnish population, which is higher than the ClinGen Potassium Channel Arrhythmia VCEP PM2_Supporting threshold of <0.00001, but lower than the BS1 threshold of >0.0004, so neither criterion is met. This variant has been reported in the cardiovascular disorder literature, however, the available clinical details are not sufficient for inclusion in PS4, so the PS4_Supporting code is not yet met. The computational predictor REVEL gives a score of 0.965, which is above the ClinGen Potassium Channel Arrhythmia VCEP PP3 threshold of >0.75 and predicts a damaging effect on KCNQ1 function (PP3). The variant demonstrates 60-70% of wild-type cell surface trafficking by flow cytometry (PMID:29532034), but 140-150% of wild-type peak current density (PMID:29532034, PMID:30571187), which is not compatible with a proposed role as a disease-causing variant for long QT syndrome 1, so the PS3 code is not met. In summary, this variant meets the criteria to be classified as a variant of uncertain significance for long QT syndrome 1 based on the ACMG/AMP criteria applied, as specified by the ClinGen Potassium Channel Arrhythmia VCEP: PP3. (VCEP specifications version 1.0.0; date of approval 03/04/2025). LINK:https://erepo.genome.network/evrepo/ui/classification/CA007671/MONDO:0100316/112

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000035 (0 hom.)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Uncertain significance reviewed by expert panel U:14
• Conservation: PhyloP100: 7.46
• Publications: 13 publications found

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]

KCNQ1 Gene-Disease associations (from GenCC):

• long QT syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• long QT syndrome 1

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• Jervell and Lange-Nielsen syndrome

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Jervell and Lange-Nielsen syndrome 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• atrial fibrillation, familial, 3

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• short QT syndrome

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet
• short QT syndrome type 2

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• familial atrial fibrillation

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Jervell and Lange-Nielsen syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Specifications for KCNQ1 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PP3: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000218.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ1	NM_000218.3	MANE Select	c.590C>T	p.Pro197Leu	missense	Exon 3 of 16	NP_000209.2
	KCNQ1	NM_001406836.1		c.590C>T	p.Pro197Leu	missense	Exon 3 of 15	NP_001393765.1
	KCNQ1	NM_001406837.1		c.320C>T	p.Pro107Leu	missense	Exon 4 of 17	NP_001393766.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ1	ENST00000155840.12	TSL:1 MANE Select	c.590C>T	p.Pro197Leu	missense	Exon 3 of 16	ENSP00000155840.2	P51787-1
	KCNQ1	ENST00000335475.6	TSL:1	c.209C>T	p.Pro70Leu	missense	Exon 3 of 16	ENSP00000334497.5	P51787-2
	KCNQ1	ENST00000910997.1		c.587C>T	p.Pro196Leu	missense	Exon 3 of 16	ENSP00000581056.1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152188 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000522 AC: 13 AN: 249032 AF XY: 0.0000740

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000115

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000350 AC: 51 AN: 1459126 Hom.: 0 Cov.: 32 AF XY: 0.0000468 AC XY: 34 AN XY: 726022

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50732

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000459 AC: 51 AN: 1111964

Other (OTH) AF: 0.00 AC: 0 AN: 60372

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152188 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74346

African (AFR) AF: 0.00 AC: 0 AN: 41428

American (AMR) AF: 0.00 AC: 0 AN: 15280

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5200

South Asian (SAS) AF: 0.00 AC: 0 AN: 4838

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000441 AC: 3 AN: 68030

Other (OTH) AF: 0.00 AC: 0 AN: 2086

Alfa AF: 0.0000652 Hom.: 0

Bravo AF: 0.0000416

ExAC AF: 0.0000659 AC: 8

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
-	6	-	not provided (6)
-	3	-	Long QT syndrome (3)
-	2	-	Cardiovascular phenotype (2)
-	1	-	Beckwith-Wiedemann syndrome;C1837014:Atrial fibrillation, familial, 3;C1865019:Short QT syndrome type 2;C4551509:Jervell and Lange-Nielsen syndrome 1;C4551647:Long QT syndrome 1 (1)
-	1	-	Cardiac arrhythmia (1)
-	1	-	Long QT syndrome 1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
CardioboostArm	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D
Eigen	Pathogenic	0.72
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		7.5
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-9.2	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.75		Gain of MoRF binding (P = 0.034)
MVP		0.97
MPC		1.1
ClinPred		0.94	D
GERP RS		4.4
Varity_R		0.98
gMVP		0.98
Mutation Taster		=4/96	disease causing

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

Other links and lift over

dbSNP: rs200108320; hg19: chr11-2591970; COSMIC: COSV50103818;