NM_000218.3:c.341T>C

Variant names:

• chr11-2445439-T-C
• rs199473448
• NM_000218.3:c.341T>C

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_000218.3(KCNQ1):​c.341T>C​(p.Leu114Pro) variant causes a missense change. 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 (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 7.03

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 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.969
• PP5: Variant 11-2445439-T-C is Pathogenic according to our data. Variant chr11-2445439-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 53036.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-2445439-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.341T>C	p.Leu114Pro	missense_variant	Exon 1 of 16	ENST00000155840.12	NP_000209.2
KCNQ1	NM_001406836.1	c.341T>C	p.Leu114Pro	missense_variant	Exon 1 of 15		NP_001393765.1
KCNQ1	NM_001406838.1	c.341T>C	p.Leu114Pro	missense_variant	Exon 1 of 11		NP_001393767.1
KCNQ1	NM_001406837.1	c.-22T>C		5_prime_UTR_variant	Exon 1 of 17		NP_001393766.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.341T>C	p.Leu114Pro	missense_variant	Exon 1 of 16	1	NM_000218.3	ENSP00000155840.2
KCNQ1	ENST00000345015.4	n.118T>C		non_coding_transcript_exon_variant	Exon 1 of 3	1
KCNQ1	ENST00000496887.7	c.80T>C	p.Leu27Pro	missense_variant	Exon 2 of 16	5		ENSP00000434560.2
KCNQ1	ENST00000646564.2	c.341T>C	p.Leu114Pro	missense_variant	Exon 1 of 11			ENSP00000495806.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome Pathogenic:1

Mar 25, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 114 of the KCNQ1 protein (p.Leu114Pro). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with long QT syndrome (PMID: 12402336). ClinVar contains an entry for this variant (Variation ID: 53036). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects KCNQ1 function (PMID: 17053194, 19114714, 19841300, 25348405). 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. -

Cardiovascular phenotype Pathogenic:1

Sep 18, 2017

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.L114P variant (also known as c.341T>C), located in coding exon 1 of the KCNQ1 gene, results from a T to C substitution at nucleotide position 341. The leucine at codon 114 is replaced by proline, an amino acid with similar properties. This alteration has been reported in a long QT syndrome cohort, but clinical details were limited (Jongbloed R et al. Hum. Mutat. 2002;20:382-91). Functional studies in multiple cell types indicate that this variant causes loss of function as a result of a trafficking defect (Dahimène S et al. Circ. Res. 2006;99:1076-83). Internal structural analysis suggests that this alteration is significantly disruptive in a sensitive region and more disruptive than a nearby known pathogenic variant (Long SB et al. Nature. 2007;450(7168):376-82). 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

-

Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

This variant has been reported as associated with Long QT syndrome in the following publications (PMID:12402336;PMID:17053194;PMID:19114714). 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	1.0
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	.;D
Eigen	Uncertain	0.64
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.97	D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Benign	1.9	.;L
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-5.1	D;D
REVEL	Pathogenic	0.91
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	.;D
Vest4		0.98
MutPred		0.85		.;Gain of catalytic residue at N112 (P = 0.0576);
MVP		0.99
MPC		2.8
ClinPred		1.0	D
GERP RS		3.2
Varity_R		0.95
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: rs199473448; hg19: chr11-2466669;