9-135779411-C-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM1PM2PP3_ModeratePP5_Very_Strong

The NM_020822.3(KCNT1):c.2782C>T(p.Arg928Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,666 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: 0.0000014 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:15O:1

Conservation

PhyloP100: 3.44

Publications

19 publications found

Variant links:

Genes affected

KCNT1 (HGNC:18865): (potassium sodium-activated channel subfamily T member 1) Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. This gene encodes a sodium-activated potassium channel subunit which is thought to function in ion conductance and developmental signaling pathways. Mutations in this gene cause the early-onset epileptic disorders, malignant migrating partial seizures of infancy and autosomal dominant nocturnal frontal lobe epilepsy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2012]

KCNT1 Gene-Disease associations (from GenCC):

childhood-onset epilepsy syndrome
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
developmental and epileptic encephalopathy, 14
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
malignant migrating partial seizures of infancy
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, Orphanet
autosomal dominant nocturnal frontal lobe epilepsy 5
Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
autosomal dominant nocturnal frontal lobe epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

KCNT1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 14 ACMG points.

PM1

In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_020822.3

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.901

PP5

Variant 9-135779411-C-T is Pathogenic according to our data. Variant chr9-135779411-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 39597.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.2782C>T	p.Arg928Cys	missense_variant	Exon 24 of 31	ENST00000371757.7	NP_065873.2	Q5JUK3-3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNT1	ENST00000371757.7 link	c.2782C>T	p.Arg928Cys	missense_variant	Exon 24 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000796

AC:

AN:

251326

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461666

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727122

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.0000188

AC:

AN:

53268

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111954

Other (OTH)

AF:

0.00

AC:

AN:

60382

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.450

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000653

Hom.:

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:15Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:6

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Nov 01, 2018

CeGaT Center for Human Genetics Tuebingen

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Nov 24, 2020

Mayo Clinic Laboratories, Mayo Clinic

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

PS3, PS4_moderate, PM2, PP1, PP3, PP4 -

May 31, 2022

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Functional studies indicate that the R928C variant results in a gain of function in KCNT1 channel properties (Evely et al., 2017; Milligan et al., 2014); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 25568878, 24395520, 26740507, 24591078, 25482562, 29037447, 26140313, 26122718, 28488083, 29196578, 27029629, 20301348, 28761347, 31208268, 30804880, 30112700, Cole2021[functionalstudy], Khamdiyeva2021[casereport], 28366665, 23086396) -

Jul 30, 2024

Centre for Clinical Genetics and Genomic Diagnostics, Zealand University Hospital

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Autosomal dominant nocturnal frontal lobe epilepsy 5

Pathogenic:4Other:1

Jun 15, 2022

Institute of Human Genetics, University of Leipzig Medical Center

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

_x000D_ Criteria applied: PS3, PS4, PP3, PP4 -

GeneReviews

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

- -

Nov 01, 2012

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Jul 07, 2020

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was determined to be pathogenic according to ACMG Guidelines, 2015 [PMID:25741868]. -

Génétique des Maladies du Développement, Hospices Civils de Lyon

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Developmental and epileptic encephalopathy, 14

Pathogenic:3

Jun 14, 2024

Institute of Human Genetics, University of Leipzig Medical Center

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Criteria applied: PS3,PS4,PS2_SUP,PP3 -

May 04, 2022

Mendelics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

May 06, 2021

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0101 - Gain of function is a known mechanism of disease in this gene and is associated with nocturnal frontal lobe epilepsy 5 (MIM#615005) and early infantile epileptic encephalopathy 14, (MIM#614959) (PMID: 24591078). Both phenotypes have been shown to be caused by the same variant within the same family (GeneReview). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0115 - Variants in this gene are known to have variable expressivity (PMID: 26122718). (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to cysteine. (I) 0251 - This variant is heterozygous. (I) 0302 - Variant is present in gnomAD (v2) <0.001 for a dominant condition (2 heterozygotes, 0 homozygotes). (SP) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (v3) (1 heterozygote, 0 homozygotes). (I) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0604 - Variant is not located in an established domain, motif, hotspot or informative constraint region. (I) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been reported in multiple individuals with nocturnal frontal lobe epilepsy (ClinVar, PMID: 23086396, 26122718). (SP) 0901 - This variant has strong evidence for segregation with disease. This variant has been shown to segregate with nocturnal frontal lobe epilepsy in one family (PMID: 23086396). (SP) 1002 - This variant has moderate functional evidence supporting abnormal protein function. Functional studies using patch clamp analysis showed that mutant protein causes an increased current amplitude and modulated channel activation and deactivation kinetics. However, patch clamp assays have been shown to be unreliable, therefore results from these studies are used with caution during variant classification (PMID: 24591078). (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Developmental and epileptic encephalopathy, 14;C3554306:Autosomal dominant nocturnal frontal lobe epilepsy 5

Pathogenic:1

Apr 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 928 of the KCNT1 protein (p.Arg928Cys). This variant is present in population databases (rs397515405, gnomAD 0.006%). This missense change has been observed in individual(s) with autosomal dominant nocturnal frontal lobe epilepsy (PMID: 23086396, 26122718). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 39597). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on KCNT1 protein function. Experimental studies have shown that this missense change affects KCNT1 function (PMID: 24591078, 25482562). For these reasons, this variant has been classified as Pathogenic. -

Seizure

Pathogenic:1

Jun 19, 2024

Génétique des Maladies du Développement, Hospices Civils de Lyon

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.30

BayesDel_noAF

Pathogenic

0.36

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.58

.;.;.;.;.;.;.;.;D;.

Eigen

Uncertain

0.53

Eigen_PC

Uncertain

0.42

FATHMM_MKL

Uncertain

0.87

LIST_S2

Pathogenic

1.0

D;D;D;D;D;D;D;D;D;D

M_CAP

Pathogenic

0.68

MetaRNN

Pathogenic

0.90

D;D;D;D;D;D;D;D;D;D

MetaSVM

Uncertain

0.36

MutationAssessor

Uncertain

2.7

.;.;.;.;.;.;.;.;M;.

PhyloP100

3.4

PrimateAI

Pathogenic

0.91

PROVEAN

Pathogenic

-7.0

.;.;D;.;.;.;.;.;D;D

REVEL

Pathogenic

0.83

Sift

Pathogenic

0.0

.;.;D;.;.;.;.;.;D;D

Sift4G

Pathogenic

0.0

D;D;D;D;D;D;D;D;D;D

Polyphen

1.0

.;.;.;.;.;.;.;.;D;.

Vest4

0.89

MutPred

0.72

.;.;.;.;.;.;Loss of MoRF binding (P = 0.0262);Loss of MoRF binding (P = 0.0262);Loss of MoRF binding (P = 0.0262);.;

MVP

0.85

MPC

1.9

ClinPred

0.95

GERP RS

2.6

Varity_R

0.85

gMVP

0.97

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.23

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.23

Position offset: 12

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over