rs199473388

Positions:

• chr17-70175965-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PP2 PP3_Strong PP5_Moderate

The NM_000891.3(KCNJ2):​c.926C>T​(p.Thr309Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,880 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNJ2 NM_000891.3 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1 O:1
• Conservation: PhyloP100: 7.91

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.

• 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, 0.981
• PP5: Variant 17-70175965-C-T is Pathogenic according to our data. Variant chr17-70175965-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 67593.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-70175965-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNJ2	NM_000891.3	c.926C>T	p.Thr309Ile	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.926C>T	p.Thr309Ile	missense_variant	2/2	1	NM_000891.3	ENSP00000243457	P1
KCNJ2	ENST00000535240.1	c.926C>T	p.Thr309Ile	missense_variant	2/2	1		ENSP00000441848	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461880 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727244

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.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 24, 2023

For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects KCNJ2 function (PMID: 15831539). 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 not expected to disrupt KCNJ2 protein function. ClinVar contains an entry for this variant (Variation ID: 67593). This missense change has been observed in individuals with clinical features of KCNJ2-related conditions (PMID: 15831539, 17221872, 24861851; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 309 of the KCNJ2 protein (p.Thr309Ile). -

Congenital long QT syndrome Other:1

not provided, no classification provided

literature only

Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust

-

This variant has been reported in the following publications (PMID:15831539;PMID:17221872). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.40
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.94	D;D
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.93	.;D
M_CAP	Uncertain	0.19	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Uncertain	0.77	D
MutationAssessor	Uncertain	2.7	M;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-4.1	D;D
REVEL	Pathogenic	0.81
Sift	Benign	0.051	T;T
Sift4G	Benign	0.24	T;T
Polyphen		1.0	D;D
Vest4		0.98
MutPred		0.87		Loss of disorder (P = 0.0886);Loss of disorder (P = 0.0886);
MVP		0.96
MPC		2.0
ClinPred		0.84	D
GERP RS		5.8
Varity_R		0.47
gMVP		0.88

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: rs199473388; hg19: chr17-68172106;