rs199473381

Positions:

• chr17-70175605-G-A
• chr17-70175605-G-C
• chr17-70175605-G-T

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_000891.3(KCNJ2):​c.566G>A​(p.Arg189Lys) variant causes a missense change involving the alteration of a 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 (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNJ2 NM_000891.3 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 10.0

Genes affected

KCNJ2 (HGNC:6263): (potassium inwardly rectifying channel subfamily J member 2) Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein, which has a greater tendency to allow potassium to flow into a cell rather than out of a cell, probably participates in establishing action potential waveform and excitability of neuronal and muscle tissues. Mutations in this gene have been associated with Andersen syndrome, which is characterized by periodic paralysis, cardiac arrhythmias, and dysmorphic features. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 15 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), KCNJ2. . Gene score misZ 2.7459 (greater than the threshold 3.09). Trascript score misZ 3.9347 (greater than threshold 3.09). GenCC has associacion of gene with long QT syndrome, short QT syndrome, Andersen-Tawil syndrome, familial atrial fibrillation, short QT syndrome type 3, catecholaminergic polymorphic ventricular tachycardia.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.951
• PP5: Variant 17-70175605-G-A is Pathogenic according to our data. Variant chr17-70175605-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 190812.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNJ2	NM_000891.3	c.566G>A	p.Arg189Lys	missense_variant	2/2	ENST00000243457.4	NP_000882.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNJ2	ENST00000243457.4	c.566G>A	p.Arg189Lys	missense_variant	2/2	1	NM_000891.3	ENSP00000243457.2
KCNJ2	ENST00000535240.1	c.566G>A	p.Arg189Lys	missense_variant	2/2	1		ENSP00000441848.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Andersen Tawil syndrome;C1865018:Short QT syndrome type 3 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 24, 2022

This sequence change replaces arginine, which is basic and polar, with lysine, which is basic and polar, at codon 189 of the KCNJ2 protein (p.Arg189Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Anderson-Tawil sydnrome (Invitae). ClinVar contains an entry for this variant (Variation ID: 190812). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt KCNJ2 protein function. This variant disrupts the p.Arg189 amino acid residue in KCNJ2. Other variant(s) that disrupt this residue have been observed in individuals with KCNJ2-related conditions (PMID: 12796536, 27145478), which suggests that this may be a clinically significant amino acid residue. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 21, 2013

p.Arg189Lys (AGA>AAA): c.566 G>A in exon 2 of the KCNJ2 gene (NM_000891.2). The Arg189Lys variant in the KCNJ2 gene has not been reported as a disease-causing mutation or as a benign polymorphism to our knowledge. Although Arg189Lys results in a conservative amino acid substitution of one positively charged amino acid with another, it occurs at a position that is conserved across species. In silico analysis predicts Arg189Lys is probably damaging to the protein structure/function. Mutations at this codon (Arg189Ile) and in nearby residues (Pro186Leu, Thr192Ala, Thr192Ile) have been reported in association with ATS, further supporting the functional importance of this codon and this region of the protein. Furthermore, the Arg189Lys variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. In summary, while Arg189Lys is a good candidate for a disease-causing mutation, with the information available at this time we cannot unequivocally determine the clinical significance of this variant. The variant is found in LQT panel(s). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D;D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	.;D
M_CAP	Pathogenic	0.34	D
MetaRNN	Pathogenic	0.95	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	M;M
PrimateAI	Pathogenic	0.91	D
PROVEAN	Uncertain	-2.9	D;D
REVEL	Pathogenic	0.89
Sift	Uncertain	0.0010	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.85
MutPred		0.86		Gain of methylation at R189 (P = 0.0293);Gain of methylation at R189 (P = 0.0293);
MVP		0.99
MPC		2.0
ClinPred		0.99	D
GERP RS		5.7
Varity_R		0.85
gMVP		0.99

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: rs199473381; hg19: chr17-68171746;