rs199473459

Variant names:

• chr11-2572071-T-C
• rs199473459
• NM_000218.3:c.742T>C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000218.3(KCNQ1):​c.742T>C​(p.Trp248Arg) 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W248F) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 5.65

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 18 ACMG points.

• PM1: In a helix (size 11) in uniprot entity KCNQ1_HUMAN there are 16 pathogenic changes around while only 0 benign (100%) 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 chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 11-2572071-T-C is Pathogenic according to our data. Variant chr11-2572071-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 67101.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-2572071-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.742T>C	p.Trp248Arg	missense_variant	Exon 5 of 16	ENST00000155840.12	NP_000209.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.742T>C	p.Trp248Arg	missense_variant	Exon 5 of 16	1	NM_000218.3	ENSP00000155840.2
KCNQ1	ENST00000335475.6	c.361T>C	p.Trp121Arg	missense_variant	Exon 5 of 16	1		ENSP00000334497.5
KCNQ1	ENST00000496887.7	c.481T>C	p.Trp161Arg	missense_variant	Exon 6 of 16	5		ENSP00000434560.2
KCNQ1	ENST00000646564.2	c.478-11364T>C		intron_variant	Intron 2 of 10			ENSP00000495806.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

May 15, 2012

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Trp248Arg (TGG>CGG): c.742 T>C in exon 5 of the KCNQ1 gene (NM_000218.2). The Trp248Arg mutation in the KCNQ1 gene has been reported in association with LQTS, and this mutation was absent from 400 control alleles (Franqueza L et al., 1999; Splawski I et al., 2000). In addition, the NHLBI ESP Exome Variant Server reports Trp248Arg was not observed in approximately 5,300 samples from individuals of European and African American backgrounds, indicating it is not a common benign variant in these populations. Functional studies have reported that Trp248Arg suppresses the ion current and results in a loss of normal channel function (Franqueza L et al., 1999; Seebohm G et al., 2003). Trp248Arg results in a non-conservative amino acid substitution of a non-polar Tryptophan with a positively charged Arginine at a residue that is conserved across species. Different missense mutations at the same codon (Trp248Cys) as well as in neighboring codons (Arg243Pro, Arg243Ser, Leu250His, Leu250Pro) have also been reported in association with LQTS, further supporting the functional importance of this region of the protein. In summary, Trp248Arg in the KCNQ1 gene is interpreted as a disease-causing mutation. The variant is found in LQT panel(s). -

Long QT syndrome Pathogenic:1

Mar 10, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces tryptophan, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 248 of the KCNQ1 protein (p.Trp248Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with long QT syndrome (PMID: 10973849). ClinVar contains an entry for this variant (Variation ID: 67101). 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. Experimental studies have shown that this missense change affects KCNQ1 function (PMID: 10409658, 14576198). 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. -

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:10409658;PMID:10973849). 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	0.54	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	.;D;.
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.97	D;D;D
M_CAP	Pathogenic	0.86	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.5	.;M;.
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-14	D;D;D
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	.;D;D
Vest4		1.0, 0.99
MutPred		0.95		.;Gain of disorder (P = 0.0033);.;
MVP		1.0
MPC		1.6
ClinPred		1.0	D
GERP RS		4.1
Varity_R		0.98
gMVP		0.97

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs199473459; hg19: chr11-2593301;