rs199473408

Positions:

• chr11-2585266-C-A

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP3_Strong PP5

The NM_000218.3(KCNQ1):​c.1087C>A​(p.His363Asn) variant causes a missense change involving the alteration of a conserved nucleotide. 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. H363H) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1 O:1
• Conservation: PhyloP100: 7.39

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 9 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_000218.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.976
• PP5: Variant 11-2585266-C-A is Pathogenic according to our data. Variant chr11-2585266-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 52954.We mark this variant Likely_pathogenic, oryginal submissions are: {not_provided=1, Pathogenic=1, Uncertain_significance=1}. Variant chr11-2585266-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ1	NM_000218.3	c.1087C>A	p.His363Asn	missense_variant	8/16	ENST00000155840.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ1	ENST00000155840.12	c.1087C>A	p.His363Asn	missense_variant	8/16	1	NM_000218.3	P1
KCNQ1	ENST00000335475.6	c.706C>A	p.His236Asn	missense_variant	8/16	1
KCNQ1	ENST00000496887.7	c.771+1721C>A		intron_variant		5
KCNQ1	ENST00000646564.2	c.588+1721C>A		intron_variant

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jan 16, 2013

p.His363Asn (CAC>AAC): c.1087 C>A in exon 8 of the KCNQ1 gene (NM_000218.2). The H363N mutation in the KCNQ1 gene has been reported in individuals with LQTS (Struijk J et al., 2006; Hedley P et al., 2009; Christiansen M et al., 2014). In addition, the H363N mutation was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. H363N results in a semi-conservative amino acid substitution, which may impact secondary protein structure as these residues differ in some properties. Mutations in nearby residues (R360G, R360M, R360T, K362R, N365H) have been reported in association with LQTS, further supporting the functional importance of this region of the protein. The variant is found in LQT panel(s). -

Long QT syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 08, 2021

This variant is not present in population databases (ExAC no frequency). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Experimental studies have shown that this missense change affects KCNQ1 function (PMID: 23861489). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C15"). ClinVar contains an entry for this variant (Variation ID: 52954). This missense change has been observed in individual(s) with long QT syndrome (PMID: 19490272, 19862833, 24357532). This sequence change replaces histidine with asparagine at codon 363 of the KCNQ1 protein (p.His363Asn). The histidine residue is highly conserved and there is a small physicochemical difference between histidine and asparagine. -

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:16937190;PMID:19862833). 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	0.29	D
BayesDel_noAF	Pathogenic	0.18
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.91	D;.
Eigen	Pathogenic	0.72
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.93	D;D
M_CAP	Pathogenic	0.96	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	2.9	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-6.3	D;D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.0040	D;D
Polyphen		0.99	D;D
Vest4		0.90
MutPred		0.83		Loss of helix (P = 0.0237);.;
MVP		0.97
MPC		1.2
ClinPred		1.0	D
GERP RS		3.8
Varity_R		0.98
gMVP		0.94

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs199473408; hg19: chr11-2606496;