11-2445103-C-T

Variant names:

• chr11-2445103-C-T
• rs199473442
• NM_000218.3:c.5C>T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000218.3(KCNQ1):​c.5C>T​(p.Ala2Val) variant causes a missense change involving the alteration of a non-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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: 0.301

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 Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.912

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.5C>T	p.Ala2Val	missense_variant	Exon 1 of 16	ENST00000155840.12	NP_000209.2
KCNQ1	NM_001406836.1	c.5C>T	p.Ala2Val	missense_variant	Exon 1 of 15		NP_001393765.1
KCNQ1	NM_001406838.1	c.5C>T	p.Ala2Val	missense_variant	Exon 1 of 11		NP_001393767.1
KCNQ1	NM_001406837.1	c.-358C>T		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.5C>T	p.Ala2Val	missense_variant	Exon 1 of 16	1	NM_000218.3	ENSP00000155840.2
KCNQ1	ENST00000646564.2	c.5C>T	p.Ala2Val	missense_variant	Exon 1 of 11			ENSP00000495806.2
KCNQ1	ENST00000496887.7	c.24-280C>T		intron_variant	Intron 1 of 15	5		ENSP00000434560.2
KCNQ1	ENST00000345015.4	n.-219C>T		upstream_gene_variant		1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 940004 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 442666

Gnomad4 AFR exome AF: 0.00

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.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

May 27, 2014

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Ala2Val (GCC>GTC): c.5 C>T in exon 1 of the KCNQ1 gene (NM_000218.2). Mutations in the KCNQ1 gene have been reported in approximately 39%-62% of patients with LQTS, and are associated with increased risk of cardiac events triggered by emotion, exercise and vigorous activity, particularly swimming (Priori et al., 2004; Vincent G, 2009). The A2V variant in the KCNQ1 gene has been reported previously as a disease causing mutation in one patient with LQTS, and was not reported in at least 2,600 control alleles (Kapplinger et al., 2009). In addition, the A2V variant was not observed in approximately 1,000 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Furthermore, missense mutations in nearby residues (M1T, P7S) have been reported in association with KCNQ1-related disorders, supporting the functional importance of this region of the protein. Nevertheless, the A2V variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. Additionally, this substitution occurs at a position that is not conserved across species. Moreover, in silico analysis predicts this variant likely does not alter the protein structure/function. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic mutation or a rare benign variant. The variant is found in LQT panel(s). -

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:19716085;PMID:22429796). 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	Uncertain	0.50
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.29	T
Eigen	Benign	-0.52
Eigen_PC	Benign	-0.52
FATHMM_MKL	Benign	0.12	N
LIST_S2	Benign	0.49	T
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.91	D
MetaSVM	Uncertain	0.74	D
MutationAssessor	Benign	0.34	N
PrimateAI	Pathogenic	0.87	D
PROVEAN	Benign	-0.36	N
REVEL	Pathogenic	0.67
Sift	Benign	0.17	T
Sift4G	Benign	0.26	T
Polyphen		0.14	B
Vest4		0.73
MutPred		0.73		Gain of sheet (P = 0.0166);
MVP		0.92
MPC		1.2
ClinPred		0.35	T
GERP RS		1.7
Varity_R		0.031
gMVP		0.39

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: rs199473442; hg19: chr11-2466333;