rs1555603969

chr17-70175707-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_000891.3(KCNJ2):c.668T>G(p.Val223Gly) 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNJ2 NM_000891.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.02

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 Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000891.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, KCNJ2
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.982

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNJ2	NM_000891.3	c.668T>G	p.Val223Gly	missense_variant	2/2	ENST00000243457.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNJ2	ENST00000243457.4	c.668T>G	p.Val223Gly	missense_variant	2/2	1	NM_000891.3	P1
KCNJ2	ENST00000535240.1	c.668T>G	p.Val223Gly	missense_variant	2/2	1		P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 31, 2017

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 do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with KCNJ2-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces valine with glycine at codon 223 of the KCNJ2 protein (p.Val223Gly). The valine residue is highly conserved and there is a moderate physicochemical difference between valine and glycine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
Cadd	Uncertain	26
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D;D
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.61	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.7	H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-6.7	D;D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;D
Vest4		0.72
MutPred		0.91		Loss of stability (P = 0.0034);Loss of stability (P = 0.0034);
MVP		1.0
MPC		2.2
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.97
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: rs1555603969; hg19: chr17-68171848;