11-2445192-A-T

Position:

• chr11-2445192-A-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000218.3(KCNQ1):​c.94A>T​(p.Lys32Ter) variant causes a stop gained 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 Pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNQ1 NM_000218.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 0.445

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.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 471 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-2445192-A-T is Pathogenic according to our data. Variant chr11-2445192-A-T is described in ClinVar as [Pathogenic]. Clinvar id is 523769.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.94A>T	p.Lys32Ter	stop_gained	1/16	ENST00000155840.12	NP_000209.2
KCNQ1	NM_001406836.1	c.94A>T	p.Lys32Ter	stop_gained	1/15		NP_001393765.1
KCNQ1	NM_001406838.1	c.94A>T	p.Lys32Ter	stop_gained	1/11		NP_001393767.1
KCNQ1	NM_001406837.1	c.-269A>T		5_prime_UTR_variant	1/17		NP_001393766.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.94A>T	p.Lys32Ter	stop_gained	1/16	1	NM_000218.3	ENSP00000155840	P1
KCNQ1	ENST00000646564.2	c.94A>T	p.Lys32Ter	stop_gained	1/11			ENSP00000495806
KCNQ1	ENST00000496887.7	c.24-191A>T		intron_variant		5		ENSP00000434560

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Apr 02, 2018

The K32X variant in the KCNQ1 gene has been reported previously in an individual with long QT syndrome (Chae et al., 2017). This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The K32X variant is not observed in large population cohorts (Lek et al., 2016). We interpret K32X as a pathogenic variant. -

Long QT syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 17, 2017

For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in KCNQ1 are known to be pathogenic (PMID: 9323054, 19862833). This variant has not been reported in the literature in individuals with KCNQ1-related disease. While this variant is not present in population databases, the frequency information is unreliable, as metrics indicate poor data quality at this position in the ExAC database. This sequence change creates a premature translational stop signal (p.Lys32*) in the KCNQ1 gene. It is expected to result in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
CADD	Pathogenic	36
DANN	Uncertain	0.99
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.27
FATHMM_MKL	Benign	0.64	D
MutationTaster	Benign	1.0	A
Vest4		0.55
GERP RS		2.7

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: rs1554958043; hg19: chr11-2466422;