9-135786407-G-A

Variant names:

Variant summary

Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBS1BS2

The NM_020822.3(KCNT1):c.3388G>A(p.Ala1130Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0123 in 1,576,966 control chromosomes in the GnomAD database, including 159 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A1130V) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0098 ( 15 hom., cov: 33)

Exomes 𝑓: 0.013 ( 144 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:14

Conservation

PhyloP100: 1.13

Publications

10 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 -20 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.004505396).

BP6

Variant 9-135786407-G-A is Benign according to our data. Variant chr9-135786407-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 129364.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS1

Variant frequency is greater than expected in population amr. GnomAd4 allele frequency = 0.00978 (1489/152318) while in subpopulation AMR AF = 0.0142 (217/15312). AF 95% confidence interval is 0.0126. There are 15 homozygotes in GnomAd4. There are 747 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High AC in GnomAd4 at 1489 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.3388G>A	p.Ala1130Thr	missense_variant	Exon 29 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.3388G>A	p.Ala1130Thr	missense_variant	Exon 29 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.00980

AC:

1491

AN:

152202

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00285

Gnomad AMI

AF:

0.0132

Gnomad AMR

AF:

0.0142

Gnomad ASJ

AF:

0.00662

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00911

Gnomad FIN

AF:

0.0121

Gnomad MID

AF:

0.0159

Gnomad NFE

AF:

0.0133

Gnomad OTH

AF:

0.0191

GnomAD2 exomes

AF:

0.0104

AC:

1844

AN:

176890

AF XY:

0.0106

show subpopulations

Gnomad AFR exome

AF:

0.00315

Gnomad AMR exome

AF:

0.00814

Gnomad ASJ exome

AF:

0.00845

Gnomad EAS exome

AF:

0.0000745

Gnomad FIN exome

AF:

0.0148

Gnomad NFE exome

AF:

0.0140

Gnomad OTH exome

AF:

0.0115

GnomAD4 exome

AF:

0.0126

AC:

17924

AN:

1424648

Hom.:

144

Cov.:

AF XY:

0.0125

AC XY:

8818

AN XY:

705736

show subpopulations

African (AFR)

AF:

0.00199

AC:

AN:

32602

American (AMR)

AF:

0.00988

AC:

393

AN:

39766

Ashkenazi Jewish (ASJ)

AF:

0.00772

AC:

197

AN:

25512

East Asian (EAS)

AF:

0.00

AC:

AN:

37690

South Asian (SAS)

AF:

0.00887

AC:

732

AN:

82522

European-Finnish (FIN)

AF:

0.0136

AC:

665

AN:

48808

Middle Eastern (MID)

AF:

0.0163

AC:

AN:

4780

European-Non Finnish (NFE)

AF:

0.0137

AC:

15023

AN:

1094112

Other (OTH)

AF:

0.0131

AC:

771

AN:

58856

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.489

Heterozygous variant carriers

1103

2205

3308

4410

5513

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

568

1136

1704

2272

2840

<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:

0.00978

AC:

1489

AN:

152318

Hom.:

Cov.:

AF XY:

0.0100

AC XY:

747

AN XY:

74482

show subpopulations

African (AFR)

AF:

0.00284

AC:

118

AN:

41588

American (AMR)

AF:

0.0142

AC:

217

AN:

15312

Ashkenazi Jewish (ASJ)

AF:

0.00662

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5170

South Asian (SAS)

AF:

0.00911

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.0121

AC:

128

AN:

10622

Middle Eastern (MID)

AF:

0.0171

AC:

AN:

292

European-Non Finnish (NFE)

AF:

0.0133

AC:

902

AN:

68006

Other (OTH)

AF:

0.0184

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.504

Heterozygous variant carriers

158

236

315

394

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

Variant carriers

100

<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:

0.00751

Hom.:

Bravo

AF:

0.00951

TwinsUK

AF:

0.0108

AC:

ALSPAC

AF:

0.0145

AC:

ESP6500AA

AF:

0.00246

AC:

ESP6500EA

AF:

0.0106

AC:

ExAC

AF:

0.00790

AC:

909

Asia WGS

AF:

0.00491

AC:

AN:

3476

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:14

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:5

Jul 17, 2014

Eurofins Ntd Llc (ga)

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Genetic Services Laboratory, University of Chicago

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

Likely benign based on allele frequency in 1000 Genomes Project or ESP global frequency and its presence in a patient with a rare or unrelated disease phenotype. NOT Sanger confirmed. -

Jan 14, 2016

GeneDx

Significance: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. -

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

PreventionGenetics, part of Exact Sciences

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Benign:4

Jun 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

KCNT1: BP4, BS1, BS2 -

Breakthrough Genomics, Breakthrough Genomics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:not provided

- -

Dec 15, 2016

Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Autosomal dominant nocturnal frontal lobe epilepsy 5

Benign:2

Mar 15, 2022

Genome-Nilou Lab

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jul 05, 2019

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was classified as: Benign. The following ACMG criteria were applied in classifying this variant: BS1,BS2. -

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

Benign:1

Feb 04, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Inborn genetic diseases

Benign:1

Apr 15, 2016

Ambry Genetics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Developmental and epileptic encephalopathy, 14

Benign:1

Mar 15, 2022

Genome-Nilou Lab

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.073

BayesDel_addAF

Benign

-0.62

BayesDel_noAF

Benign

-0.65

CADD

Benign

5.0

(source)

DANN

Benign

0.90

DEOGEN2

Benign

0.030

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

Eigen

Benign

-1.6

Eigen_PC

Benign

-1.7

FATHMM_MKL

Benign

0.13

LIST_S2

Benign

0.74

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

MetaRNN

Benign

0.0045

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

MetaSVM

Benign

-1.0

MutationAssessor

Uncertain

2.2

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

PhyloP100

1.1

PrimateAI

Benign

0.36

PROVEAN

Benign

-0.67

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

REVEL

Benign

0.028

Sift

Uncertain

0.012

D;.;T;.;.;.;.;.;.;T

Sift4G

Benign

0.45

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

Vest4

0.25

MPC

0.092

ClinPred

0.0033

GERP RS

-1.1

Varity_R

0.028

gMVP

0.37

Mutation Taster

=100/0

polymorphism

(source)

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

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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