chr9-135771015-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.1928G>A(p.Arg643Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000175 in 1,613,664 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 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. R643W) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00022 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00017 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:4

Conservation

PhyloP100: 2.94

Publications

2 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=0.0140633285).

BP6

Variant 9-135771015-G-A is Benign according to our data. Variant chr9-135771015-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 386260.

BS1

Variant frequency is greater than expected in population mid. GnomAdExome4 allele frequency = 0.00017 (248/1461346) while in subpopulation MID AF = 0.000694 (4/5766). AF 95% confidence interval is 0.000236. There are 0 homozygotes in GnomAdExome4. There are 125 alleles in the male GnomAdExome4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High AC in GnomAd4 at 34 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020822.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNT1	NM_020822.3	MANE Select	c.1928G>A	p.Arg643Gln	missense	Exon 18 of 31	NP_065873.2
	KCNT1	NM_001272003.2		c.1793G>A	p.Arg598Gln	missense	Exon 17 of 31	NP_001258932.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNT1	ENST00000371757.7	TSL:1 MANE Select	c.1928G>A	p.Arg643Gln	missense	Exon 18 of 31	ENSP00000360822.2
KCNT1	ENST00000460750.5	TSL:1	n.*1538G>A		non_coding_transcript_exon	Exon 18 of 32	ENSP00000418777.1
KCNT1	ENST00000460750.5	TSL:1	n.*1538G>A		3_prime_UTR	Exon 18 of 32	ENSP00000418777.1

Frequencies

GnomAD3 genomes

AF:

0.000204

AC:

AN:

152200

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000169

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

Gnomad ASJ

AF:

0.00173

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.000162

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.000233

AC:

AN:

248562

AF XY:

0.000200

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000145

Gnomad ASJ exome

AF:

0.00180

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000276

Gnomad OTH exome

AF:

0.000330

GnomAD4 exome

AF:

0.000170

AC:

248

AN:

1461346

Hom.:

Cov.:

AF XY:

0.000172

AC XY:

125

AN XY:

726934

show subpopulations

African (AFR)

AF:

0.000149

AC:

AN:

33472

American (AMR)

AF:

0.000179

AC:

AN:

44658

Ashkenazi Jewish (ASJ)

AF:

0.00153

AC:

AN:

26126

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39682

South Asian (SAS)

AF:

0.0000929

AC:

AN:

86142

European-Finnish (FIN)

AF:

0.0000187

AC:

AN:

53336

Middle Eastern (MID)

AF:

0.000694

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.000149

AC:

166

AN:

1111780

Other (OTH)

AF:

0.000248

AC:

AN:

60384

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.468

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:

0.000223

AC:

AN:

152318

Hom.:

Cov.:

AF XY:

0.000228

AC XY:

AN XY:

74476

show subpopulations

African (AFR)

AF:

0.000216

AC:

AN:

41580

American (AMR)

AF:

0.000261

AC:

AN:

15302

Ashkenazi Jewish (ASJ)

AF:

0.00173

AC:

AN:

3472

East Asian (EAS)

AF:

0.000194

AC:

AN:

5162

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00340

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000176

AC:

AN:

68032

Other (OTH)

AF:

0.000473

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.485

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:

0.000460

Hom.:

Bravo

AF:

0.000272

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.000465

AC:

ExAC

AF:

0.000297

AC:

EpiCase

AF:

0.000218

EpiControl

AF:

0.000416

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:2

May 01, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 28166811)

Nov 03, 2021

Institute for Clinical Genetics, University Hospital TU Dresden, University Hospital TU Dresden

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Dec 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

KCNT1: BP4

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

Benign:1

Dec 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Inborn genetic diseases

Benign:1

May 10, 2022

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.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.056

BayesDel_addAF

Benign

-0.55

BayesDel_noAF

Benign

-0.72

CADD

Benign

(source)

DANN

Benign

0.32

DEOGEN2

Benign

0.022

Eigen

Benign

-1.1

Eigen_PC

Benign

-0.99

FATHMM_MKL

Benign

0.29

LIST_S2

Uncertain

0.92

M_CAP

Uncertain

0.093

MetaRNN

Benign

0.014

MetaSVM

Benign

-0.95

MutationAssessor

Benign

-1.1

PhyloP100

2.9

PrimateAI

Benign

0.35

PROVEAN

Benign

0.89

REVEL

Benign

0.053

Sift

Benign

1.0

Sift4G

Benign

1.0

Polyphen

0.0

Vest4

0.16

MVP

0.32

MPC

0.73

ClinPred

0.013

GERP RS

0.17

Varity_R

0.026

gMVP

0.20

Mutation Taster

=91/9

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over