rs786204778

Positions:

• chr11-2572890-CT-C

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000218.3(KCNQ1):​c.826delT​(p.Ser276fs) variant causes a frameshift change. The variant allele was found at a frequency of 0.000000684 in 1,461,464 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★). 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 frameshift
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.70

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 12 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 11-2572890-CT-C is Pathogenic according to our data. Variant chr11-2572890-CT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 189232.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr11-2572890-CT-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.826delT	p.Ser276fs	frameshift_variant	6/16	ENST00000155840.12	NP_000209.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.826delT	p.Ser276fs	frameshift_variant	6/16	1	NM_000218.3	ENSP00000155840.2
KCNQ1	ENST00000335475.6	c.445delT	p.Ser149fs	frameshift_variant	6/16	1		ENSP00000334497.5
KCNQ1	ENST00000496887.7	c.565delT	p.Ser189fs	frameshift_variant	7/16	5		ENSP00000434560.2
KCNQ1	ENST00000646564.2	c.478-10544delT		intron_variant				ENSP00000495806.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250436 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135698

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000463

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461464 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727050

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: 0.0000189

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Jervell and Lange-Nielsen syndrome;C1141890:Congenital long QT syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Dec 09, 2013

The Ser276ProfsX13 variant in KCNQ1 has not been previously reported in the lite rature or in large population studies. This frameshift variant is predicted to a lter the protein?s amino acid sequence beginning at position 276 and lead to a p remature termination codon 13 amino acids downstream. This alteration is then pr edicted to lead to a truncated or absent protein. Complete loss of KCNQ1 functi on leads to Jervell and Lange-Nielsen syndrome (JLNS) in compound heterozygous a nd homozygous individuals while dominant-negative and loss-of-function variants in KCNQ1 have been shown to lead to Romano-Ward syndrome (RWS) in heterozygous i ndividuals. In summary, this variant is likely pathogenic, though additional stu dies are required to fully establish its clinical significance. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs786204778; hg19: chr11-2594120;