11-2570663-C-A

Position:

• chr11-2570663-C-A

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.513C>A​(p.Tyr171Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,326 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. Y171Y) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNQ1 NM_000218.3 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: -0.505

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 undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-2570663-C-A is Pathogenic according to our data. Variant chr11-2570663-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 265209.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ1	NM_000218.3	c.513C>A	p.Tyr171Ter	stop_gained	3/16	ENST00000155840.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ1	ENST00000155840.12	c.513C>A	p.Tyr171Ter	stop_gained	3/16	1	NM_000218.3	P1
KCNQ1	ENST00000335475.6	c.132C>A	p.Tyr44Ter	stop_gained	3/16	1
KCNQ1	ENST00000496887.7	c.252C>A	p.Tyr84Ter	stop_gained	4/16	5
KCNQ1	ENST00000646564.2	c.478-12772C>A		intron_variant

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460326 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726568

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome 1 Pathogenic:2

Pathogenic, no assertion criteria provided	research	Division of Human Genetics, Children's Hospital of Philadelphia	Feb 25, 2016	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	MGZ Medical Genetics Center	Jun 24, 2022	- -

Long QT syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 17, 2024	This sequence change creates a premature translational stop signal (p.Tyr171*) in the KCNQ1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in KCNQ1 are known to be pathogenic (PMID: 9323054, 19862833). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with Jervell and Lange-Nielsen syndrome and/or long QT syndrome (PMID: 11216980, 12051962, 14678125, 26187847). ClinVar contains an entry for this variant (Variation ID: 265209). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Jan 08, 2024	This variant changes 1 nucleotide in exon 3 of the KCNQ1 gene, creating a premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. A functional study has shown that this variant results in undetectable expression of KCNQ1 in RNA and protein levels and no functional potassium current in transfected cells (PMID: 33504163). This variant has been reported in at least three unrelated individuals affected with long QT syndrome (PMID: 14678125, 32893267), in an individual affected with sudden cardiac arrest or death (PMID: 26187847), and in an asymptomatic individual (PMID: 33504163). A different nucleotide change (c.513C>G) leading to the same nonsense variant has been determined to be pathogenic (ClinVar variation ID 53056). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of KCNQ1 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Pathogenic. -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 08, 2017

The p.Y171* pathogenic mutation (also known as c.513C>A), located in coding exon 3 of the KCNQ1 gene, results from a C to A substitution at nucleotide position 513. This changes the amino acid from a tyrosine to a stop codon within coding exon 3. This alteration has been reported in a sudden cardiac arrest/death cohort (Li MH et al. Human Genomics, 2015 9:15). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Cardiac arrhythmia Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Jun 21, 2023

This variant changes 1 nucleotide in exon 3 of the KCNQ1 gene, creating a premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. A functional study has shown that this variant results in undetectable expression of KCNQ1 in RNA and protein levels and no functional potassium current in transfected cells (PMID: 33504163). This variant has been reported in at least three unrelated individuals affected with long QT syndrome (PMID: 14678125, 32893267), in an individual affected with sudden cardiac arrest or death (PMID: 26187847), and in an asymptomatic individual (PMID: 33504163). A different nucleotide change (c.513C>G) leading to the same nonsense variant has been determined to be pathogenic (ClinVar variation ID 53056). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of KCNQ1 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	35
DANN	Uncertain	0.99
Eigen	Benign	-0.20
Eigen_PC	Benign	-0.51
FATHMM_MKL	Benign	0.27	N
MutationTaster	Benign	1.0	A;A
Vest4		0.88, 0.85
GERP RS		-4.4

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs139042529; hg19: chr11-2591893;