chr9-135755151-G-A

Variant names:

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2

The NM_020822.3(KCNT1):c.522G>A(p.Met174Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000382 in 1,612,268 control chromosomes in the GnomAD database, including 4 homozygotes. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00036 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00038 ( 4 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:6

Conservation

PhyloP100: 0.343

Publications

4 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 -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.01074186).

BP6

Variant 9-135755151-G-A is Benign according to our data. Variant chr9-135755151-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 241304.

BS1

Variant frequency is greater than expected in population amr. GnomAd4 allele frequency = 0.000361 (55/152298) while in subpopulation AMR AF = 0.00105 (16/15292). AF 95% confidence interval is 0.000656. There are 0 homozygotes in GnomAd4. There are 26 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High AC in GnomAd4 at 55 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.522G>A	p.Met174Ile	missense_variant	Exon 6 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.522G>A	p.Met174Ile	missense_variant	Exon 6 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.000361

AC:

AN:

152180

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00105

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.000426

Gnomad OTH

AF:

0.00191

GnomAD2 exomes

AF:

0.000393

AC:

AN:

249278

AF XY:

0.000401

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00108

Gnomad ASJ exome

AF:

0.000100

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000464

Gnomad NFE exome

AF:

0.000462

Gnomad OTH exome

AF:

0.000991

GnomAD4 exome

AF:

0.000384

AC:

561

AN:

1459970

Hom.:

Cov.:

AF XY:

0.000388

AC XY:

282

AN XY:

726328

show subpopulations

African (AFR)

AF:

0.000838

AC:

AN:

33406

American (AMR)

AF:

0.00146

AC:

AN:

44452

Ashkenazi Jewish (ASJ)

AF:

0.0000768

AC:

AN:

26048

East Asian (EAS)

AF:

0.00

AC:

AN:

39604

South Asian (SAS)

AF:

0.0000349

AC:

AN:

86078

European-Finnish (FIN)

AF:

0.0000187

AC:

AN:

53350

Middle Eastern (MID)

AF:

0.00504

AC:

AN:

5756

European-Non Finnish (NFE)

AF:

0.000335

AC:

372

AN:

1110978

Other (OTH)

AF:

0.00101

AC:

AN:

60298

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.464

Heterozygous variant carriers

105

131

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome 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

GnomAD4 genome

AF:

0.000361

AC:

AN:

152298

Hom.:

Cov.:

AF XY:

0.000349

AC XY:

AN XY:

74468

show subpopulations

African (AFR)

AF:

0.000120

AC:

AN:

41570

American (AMR)

AF:

0.00105

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00340

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000426

AC:

AN:

68016

Other (OTH)

AF:

0.00189

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.509

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:

0.000535

Hom.:

Bravo

AF:

0.000638

TwinsUK

AF:

0.000539

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000349

AC:

ExAC

AF:

0.000362

AC:

EpiCase

AF:

0.000655

EpiControl

AF:

0.000474

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:6

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:2

Sep 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

KCNT1: BP4, BS1 -

Jul 11, 2016

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Sep 12, 2023

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 28, 2017

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Benign:1

Oct 12, 2017

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

Jan 28, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Inborn genetic diseases

Benign:1

Jan 07, 2019

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely 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. -

KCNT1-related disorder

Benign:1

Feb 03, 2020

PreventionGenetics, part of Exact Sciences

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Benign

-0.49

BayesDel_noAF

Benign

-0.53

CADD

Benign

(source)

DANN

Benign

0.92

DEOGEN2

Benign

0.036

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

Eigen

Benign

-0.67

Eigen_PC

Benign

-0.61

FATHMM_MKL

Benign

0.17

LIST_S2

Benign

0.85

T;D;T;T;D;T;D;D;D;D;D

M_CAP

Benign

0.025

MetaRNN

Benign

0.011

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

MetaSVM

Benign

-1.0

MutationAssessor

Benign

0.90

.;.;.;.;.;.;.;.;.;L;.

PhyloP100

0.34

PrimateAI

Benign

0.46

PROVEAN

Benign

-0.65

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

REVEL

Benign

0.045

Sift

Benign

0.20

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

Sift4G

Benign

0.29

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

Vest4

0.16

MutPred

0.47

.;.;.;.;.;.;Loss of catalytic residue at V137 (P = 0.0116);.;.;.;.;

MVP

0.29

MPC

0.71

ClinPred

0.0095

GERP RS

3.1

Varity_R

0.20

gMVP

0.62

Mutation Taster

=96/4

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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