rs397508133

Positions:

• chr11-2583433-A-C
• chr11-2583433-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_000218.3(KCNQ1):​c.922-2A>C variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as not provided (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNQ1 NM_000218.3 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: not provided no classification provided O:1
• Conservation: PhyloP100: 8.73

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.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.054160513 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.8, offset of 7, new splice context is: cctctccctgccggtcacAGtca. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.922-2A>C		splice_acceptor_variant		ENST00000155840.12	NP_000209.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.922-2A>C		splice_acceptor_variant		1	NM_000218.3	ENSP00000155840	P1
KCNQ1	ENST00000335475.6	c.541-2A>C		splice_acceptor_variant		1		ENSP00000334497
KCNQ1	ENST00000496887.7	c.661-2A>C		splice_acceptor_variant		5		ENSP00000434560
KCNQ1	ENST00000646564.2	c.478-2A>C		splice_acceptor_variant				ENSP00000495806

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Significance: not provided

Submissions summary: Other:1

Revision: no classification provided

Submissions by phenotype

Long QT syndrome 1 Other:1

not provided, no classification provided

literature only

ClinVar Staff, National Center for Biotechnology Information (NCBI)

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Uncertain	-0.030
CADD	Pathogenic	35
DANN	Uncertain	0.99
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Uncertain	0.84	D
MutationTaster	Benign	1.0	D;D
GERP RS		3.9

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.66		Position offset: 9
DS_AL_spliceai		1.0		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs397508133; hg19: chr11-2604663;