rs878853753

Positions:

• chr11-2587646-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000218.3(KCNQ1):​c.1205G>A​(p.Ser402Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,620 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.96

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 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.105181426).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.1205G>A	p.Ser402Asn	missense_variant	9/16	ENST00000155840.12	NP_000209.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.1205G>A	p.Ser402Asn	missense_variant	9/16	1	NM_000218.3	ENSP00000155840	P1
KCNQ1	ENST00000335475.6	c.824G>A	p.Ser275Asn	missense_variant	9/16	1		ENSP00000334497
KCNQ1	ENST00000496887.7	c.848G>A	p.Ser283Asn	missense_variant	9/16	5		ENSP00000434560
KCNQ1	ENST00000646564.2	c.665G>A	p.Ser222Asn	missense_variant	4/11			ENSP00000495806

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461620 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727116

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

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 16, 2022

This sequence change replaces serine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 402 of the KCNQ1 protein (p.Ser402Asn). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The asparagine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. ClinVar contains an entry for this variant (Variation ID: 237222). This missense change has been observed in individual(s) with clinical features of KCNQ1-related conditions (PMID: 29247119). This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.071
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Benign	8.6
DANN	Benign	0.68
DEOGEN2	Benign	0.30	T;.;.
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.018	N
LIST_S2	Benign	0.69	T;T;T
M_CAP	Uncertain	0.26	D
MetaRNN	Benign	0.11	T;T;T
MetaSVM	Uncertain	0.37	D
MutationAssessor	Benign	-0.36	N;.;.
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-0.040	N;.;N
REVEL	Uncertain	0.54
Sift	Benign	0.56	T;.;T
Sift4G	Benign	0.53	T;.;T
Polyphen		0.0	B;.;B
Vest4		0.11
MutPred		0.27		Loss of phosphorylation at S402 (P = 0.0188);.;.;
MVP		0.81
MPC		0.34
ClinPred		0.054	T
GERP RS		0.22
Varity_R		0.081
gMVP		0.40

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: rs878853753; hg19: chr11-2608876;