17-70175617-T-C

Variant names:

• chr17-70175617-T-C
• rs1555603955
• NM_000891.3:c.578T>C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PP2 PP3_Strong PP5

The NM_000891.3(KCNJ2):​c.578T>C​(p.Leu193Pro) 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 Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNJ2 NM_000891.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 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 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the KCNJ2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 51 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 2.7459 (below the threshold of 3.09). Trascript score misZ: 3.9347 (above the threshold of 3.09). GenCC associations: The gene is linked to 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, 0.994
• PP5: Variant 17-70175617-T-C is Pathogenic according to our data. Variant chr17-70175617-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 932125.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNJ2	NM_000891.3	c.578T>C	p.Leu193Pro	missense_variant	Exon 2 of 2	ENST00000243457.4	NP_000882.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNJ2	ENST00000243457.4	c.578T>C	p.Leu193Pro	missense_variant	Exon 2 of 2	1	NM_000891.3	ENSP00000243457.2
KCNJ2	ENST00000535240.1	c.578T>C	p.Leu193Pro	missense_variant	Exon 2 of 2	1		ENSP00000441848.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Andersen Tawil syndrome Pathogenic:1

Jan 01, 2016

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was classified as: Pathogenic. -

not provided Uncertain:1

May 23, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Reported in an individual with Andersen-Tawil syndrome in published literature (Vivekanandam et al., 2022); This variant is associated with the following publications: (PMID: 24383070, 34919635) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
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	0.86
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.96	.;D
M_CAP	Pathogenic	0.77	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.0	H;H
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-6.7	D;D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.98
MutPred		0.92		Loss of stability (P = 0.0075);Loss of stability (P = 0.0075);
MVP		1.0
MPC		2.4
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.99
gMVP		1.0

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: rs1555603955; hg19: chr17-68171758;