11-2585257-A-T

Position:

• chr11-2585257-A-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Moderate

The ENST00000155840.12(KCNQ1):​c.1078A>T​(p.Arg360Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R360G) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNQ1 ENST00000155840.12 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 2.36

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 10 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in ENST00000155840.12
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr11-2585257-A-G is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.921
• PP5: Variant 11-2585257-A-T is Pathogenic according to our data. Variant chr11-2585257-A-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 200839.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr11-2585257-A-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.1078A>T	p.Arg360Trp	missense_variant	8/16	ENST00000155840.12	NP_000209.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.1078A>T	p.Arg360Trp	missense_variant	8/16	1	NM_000218.3	ENSP00000155840	P1
KCNQ1	ENST00000335475.6	c.697A>T	p.Arg233Trp	missense_variant	8/16	1		ENSP00000334497
KCNQ1	ENST00000496887.7	c.771+1712A>T		intron_variant		5		ENSP00000434560
KCNQ1	ENST00000646564.2	c.588+1712A>T		intron_variant				ENSP00000495806

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Feb 26, 2018

Although the R360W variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge, this substitution occurs at a position that is conserved across species and is located in the S6-AB linker region at the C-terminus of the protein, a region critical for PIP2 activation of the channel (Telezhkin et al., 2013). Additionally, variants affecting the R360 residue have been reported (R360M, R360T) in association with LQTS (Stenson et al., 2014). The R360W variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Moreover, the R360W variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties, and in silico analysis predicts this variant is probably damaging to the protein structure/function. Finally, this variant was seen co-segregating with prolonged QTc intervals in six relatives in this family referred for genetic testing at GeneDx. Therefore, this variant is likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.27
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.95	D;.
Eigen	Uncertain	0.40
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Benign	0.74	D
LIST_S2	Pathogenic	1.0	D;D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.92	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	2.9	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.94	D
PROVEAN	Pathogenic	-7.4	D;D
REVEL	Pathogenic	0.83
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.89
MutPred		0.47		Loss of disorder (P = 0.0055);.;
MVP		0.98
MPC		1.2
ClinPred		1.0	D
GERP RS		1.3
Varity_R		0.92
gMVP		0.96

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: rs199473406; hg19: chr11-2606487;