NM_000218.3:c.567dupG

Variant names:

• chr11-2570712-T-TG
• rs397508117
• NM_000218.3:c.567dupG

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.567dupG​(p.Arg190AlafsTer95) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,460,082 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: KCNQ1 NM_000218.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 2.51

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 11-2570712-T-TG is Pathogenic according to our data. Variant chr11-2570712-T-TG is described in ClinVar as [Pathogenic]. Clinvar id is 53069.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.567dupG	p.Arg190AlafsTer95	frameshift_variant	Exon 3 of 16	ENST00000155840.12	NP_000209.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.567dupG	p.Arg190AlafsTer95	frameshift_variant	Exon 3 of 16	1	NM_000218.3	ENSP00000155840.2
KCNQ1	ENST00000335475.6	c.186dupG	p.Arg63AlafsTer95	frameshift_variant	Exon 3 of 16	1		ENSP00000334497.5
KCNQ1	ENST00000496887.7	c.306dupG	p.Arg103AlafsTer95	frameshift_variant	Exon 4 of 16	5		ENSP00000434560.2
KCNQ1	ENST00000646564.2	c.478-12718dupG		intron_variant	Intron 2 of 10			ENSP00000495806.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1460082 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726428

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome 1 Pathogenic:1

Aug 01, 2023

Molecular Genetics Laboratory - Cardiogenetics, CHU de Nantes

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jervell and Lange-Nielsen syndrome 1 Pathogenic:1

May 29, 1997

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

KCNQ1-related disorder Pathogenic:1

Aug 07, 2024

PreventionGenetics, part of Exact Sciences

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The KCNQ1 c.567dupG variant is predicted to result in a frameshift and premature protein termination (p.Arg190Alafs*95). This variant has been reported in the homozygous or compound heterozygous state in individuals with autosomal recessive Jervell and Lange-Nielsen syndrome and in the heterozygous state in individuals with autosomal dominant long QT syndrome (described as 282_283insG, Splawski et al. 1997. PubMed ID: 9164812; Rice et al. 2011. PubMed ID: 21118729). This variant has not been reported in a large population database, indicating this variant is rare. Frameshift variants in KCNQ1 are expected to be pathogenic. This variant is interpreted as pathogenic for both autosomal dominant and autosomal recessive KCNQ1-related disorders. -

not provided Pathogenic:1

Jan 19, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 9164812, 21118729, 19862833, 28595573, 27535533) -

Long QT syndrome Pathogenic:1

Jan 19, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Arg190Alafs*95) 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 (PMID: 9164812, 21118729). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 53069). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Cardiovascular phenotype Pathogenic:1

May 27, 2016

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.567dupG pathogenic mutation, located in coding exon 3 of the KCNQ1 gene, results from a duplication of G at nucleotide position 567, causing a translational frameshift with a predicted alternate stop codon (p.R190Afs*95). This alteration has previously been detected in multiple individuals with long QT syndrome and segregated with disease in one family, and was also identified in individuals with Jervell and Lange-Nielsen syndrome in the homozygous or compound heterozygous state with another KCNQ1 truncating mutation (Rice KS et al., Heart Rhythm 2011 Apr; 8(4):551-4; Splawski I et al., N. Engl. J. Med. 1997 May; 336(22):1562-7). In addition to the clinical data presented in the literature, since frameshifts are typically deleterious in nature, this alteration is interpreted as a disease-causing mutation (ACMG Recommendations for Standards for Interpretation and Reporting of Sequence Variations. Revision 2007. Genet Med. 2008;10:294). -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.27		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.27		Position offset: -14

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs397508117; hg19: chr11-2591942;