12-21765766-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_004982.4(KCNJ8):c.1232A>C(p.Gln411Pro) variant causes a missense change. 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: KCNJ8 NM_004982.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.79

Genes affected

KCNJ8 (HGNC:6269): (potassium inwardly rectifying channel subfamily J member 8) 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, is controlled by G-proteins. Defects in this gene may be a cause of J-wave syndromes and sudden infant death syndrome (SIDS). [provided by RefSeq, May 2012]

(HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, KCNJ8
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.786

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNJ8	NM_004982.4	c.1232A>C	p.Gln411Pro	missense_variant	3/3	ENST00000240662.3
LOC105369689	XR_007063241.1	n.631+5681T>G		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNJ8	ENST00000240662.3	c.1232A>C	p.Gln411Pro	missense_variant	3/3	1	NM_004982.4	P1
	ENST00000542489.1	n.107-590T>G		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Brugada syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 21, 2020

This variant is not present in population databases (ExAC no frequency). This sequence change replaces glutamine with proline at codon 411 of the KCNJ8 protein (p.Gln411Pro). The glutamine residue is highly conserved and there is a moderate physicochemical difference between glutamine and proline. This variant has not been reported in the literature in individuals with KCNJ8-related conditions. 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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 13, 2024

The p.Q411P variant (also known as c.1232A>C), located in coding exon 2 of the KCNJ8 gene, results from an A to C substitution at nucleotide position 1232. The glutamine at codon 411 is replaced by proline, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
Cadd	Uncertain	25
Dann	Uncertain	0.99
DEOGEN2	Benign	0.31	T
Eigen	Uncertain	0.51
Eigen_PC	Uncertain	0.59
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	D
M_CAP	Benign	0.068	D
MetaRNN	Pathogenic	0.79	D
MetaSVM	Uncertain	-0.033	T
MutationAssessor	Benign	0.97	L
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-0.85	N
REVEL	Uncertain	0.41
Sift	Uncertain	0.0040	D
Sift4G	Uncertain	0.015	D
Polyphen		0.99	D
Vest4		0.78
MutPred		0.22		Loss of sheet (P = 0.0084);
MVP		0.82
MPC		2.4
ClinPred		0.92	D
GERP RS		5.9
Varity_R		0.31
gMVP		0.83

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: rs1940602689; hg19: chr12-21918700;