9-135786300-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -11 ACMG points: 0P and 11B. BP4_ModerateBP6BS1BS2

The NM_020822.3(KCNT1):c.3281C>T(p.Thr1094Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000492 in 1,604,062 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T1094R) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00012 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000041 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:3

Conservation

PhyloP100: 1.48

Publications

1 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: Benign. The variant received -11 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.07017034).

BP6

Variant 9-135786300-C-T is Benign according to our data. Variant chr9-135786300-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 473384.

BS1

Variant frequency is greater than expected in population afr. GnomAdExome4 allele frequency = 0.0000413 (60/1451768) while in subpopulation AFR AF = 0.000389 (13/33384). AF 95% confidence interval is 0.00023. There are 0 homozygotes in GnomAdExome4. There are 26 alleles in the male GnomAdExome4 subpopulation. Median coverage is 36. This position passed quality control check.

BS2

High AC in GnomAd4 at 19 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.3281C>T	p.Thr1094Met	missense_variant	Exon 29 of 31	ENST00000371757.7	NP_065873.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNT1	ENST00000371757.7 link	c.3281C>T	p.Thr1094Met	missense_variant	Exon 29 of 31	1	NM_020822.3	ENSP00000360822.2

Frequencies

GnomAD3 genomes

AF:

0.000125

AC:

AN:

152176

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000314

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000556

AC:

AN:

215920

AF XY:

0.0000586

show subpopulations

Gnomad AFR exome

AF:

0.000338

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.000109

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000538

Gnomad OTH exome

AF:

0.000374

GnomAD4 exome

AF:

0.0000413

AC:

AN:

1451768

Hom.:

Cov.:

AF XY:

0.0000360

AC XY:

AN XY:

721342

show subpopulations

African (AFR)

AF:

0.000389

AC:

AN:

33384

American (AMR)

AF:

0.00

AC:

AN:

43554

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25842

East Asian (EAS)

AF:

0.00

AC:

AN:

39294

South Asian (SAS)

AF:

0.00

AC:

AN:

84782

European-Finnish (FIN)

AF:

0.00

AC:

AN:

50814

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5590

European-Non Finnish (NFE)

AF:

0.0000379

AC:

AN:

1108604

Other (OTH)

AF:

0.0000835

AC:

AN:

59904

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.489

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

AF:

0.000125

AC:

AN:

152294

Hom.:

Cov.:

AF XY:

0.000161

AC XY:

AN XY:

74476

show subpopulations

African (AFR)

AF:

0.000313

AC:

AN:

41576

American (AMR)

AF:

0.0000653

AC:

AN:

15310

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5170

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000735

AC:

AN:

68002

Other (OTH)

AF:

0.00

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.522

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.000135

Hom.:

Bravo

AF:

0.000166

ESP6500AA

AF:

0.000261

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000344

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

Jan 16, 2017

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Sep 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

KCNT1: BP4, BS1 -

Inborn genetic diseases

Uncertain:1

Jun 22, 2017

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.T1094M variant (also known as c.3281C>T), located in coding exon 29 of the KCNT1 gene, results from a C to T substitution at nucleotide position 3281. The threonine at codon 1094 is replaced by methionine, an amino acid with similar properties. This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

not specified

Benign:1

Jan 12, 2018

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

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

Benign:1

Oct 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.090

BayesDel_addAF

Benign

-0.46

BayesDel_noAF

Benign

-0.59

CADD

Benign

(source)

DANN

Uncertain

0.98

DEOGEN2

Benign

0.051

.;.;.;.;.;.;.;.;T;.

Eigen

Benign

-1.1

Eigen_PC

Benign

-1.2

FATHMM_MKL

Benign

0.21

LIST_S2

Benign

0.74

T;T;T;T;T;T;T;T;T;T

M_CAP

Pathogenic

0.47

MetaRNN

Benign

0.070

T;T;T;T;T;T;T;T;T;T

MetaSVM

Benign

-1.0

MutationAssessor

Benign

0.69

.;.;.;.;.;.;.;.;N;.

PhyloP100

1.5

PrimateAI

Uncertain

0.54

PROVEAN

Benign

-0.85

.;.;N;.;.;.;.;.;.;N

REVEL

Benign

0.055

Sift

Uncertain

0.0090

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

Sift4G

Uncertain

0.017

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

Vest4

0.14

MVP

0.27

MPC

0.092

ClinPred

0.032

GERP RS

-1.2

Varity_R

0.019

gMVP

0.41

Mutation Taster

=91/9

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over