chr9-135759709-G-A

Variant names:

Variant summary

Our verdict is Benign. The variant received -14 ACMG points: 0P and 14B. BP4_StrongBP6BP7BS1BS2

The NM_020822.3(KCNT1):c.885G>A(p.Ala295Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000531 in 1,611,944 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00034 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00055 ( 1 hom. )

Consequence

KCNT1
NM_020822.3 synonymous

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:6

Conservation

PhyloP100: -6.36

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 -14 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.71).

BP6

Variant 9-135759709-G-A is Benign according to our data. Variant chr9-135759709-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 193923.We mark this variant Likely_benign, oryginal submission is: [Conflicting_classifications_of_pathogenicity].

BP7

Synonymous conserved (PhyloP=-6.36 with no splicing effect.

BS1

Variant frequency is greater than expected in population amr. GnomAd4 allele frequency = 0.000342 (52/152172) while in subpopulation AMR AF = 0.000981 (15/15286). AF 95% confidence interval is 0.000604. There are 0 homozygotes in GnomAd4. There are 31 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High AC in GnomAd4 at 52 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.885G>A	p.Ala295Ala	synonymous_variant	Exon 11 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.885G>A	p.Ala295Ala	synonymous_variant	Exon 11 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.000342

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000981

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.0000941

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000456

Gnomad OTH

AF:

0.000957

GnomAD2 exomes

AF:

0.000546

AC:

136

AN:

249100

AF XY:

0.000548

show subpopulations

Gnomad AFR exome

AF:

0.0000619

Gnomad AMR exome

AF:

0.00128

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000464

Gnomad NFE exome

AF:

0.000695

Gnomad OTH exome

AF:

0.000988

GnomAD4 exome

AF:

0.000551

AC:

804

AN:

1459772

Hom.:

Cov.:

AF XY:

0.000543

AC XY:

394

AN XY:

726112

show subpopulations

African (AFR)

AF:

0.000179

AC:

AN:

33444

American (AMR)

AF:

0.00132

AC:

AN:

44592

Ashkenazi Jewish (ASJ)

AF:

0.0000768

AC:

AN:

26028

East Asian (EAS)

AF:

0.0000504

AC:

AN:

39646

South Asian (SAS)

AF:

0.000256

AC:

AN:

86098

European-Finnish (FIN)

AF:

0.0000945

AC:

AN:

52912

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5756

European-Non Finnish (NFE)

AF:

0.000590

AC:

656

AN:

1110988

Other (OTH)

AF:

0.000862

AC:

AN:

60308

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.468

Heterozygous variant carriers

138

184

230

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

104

130

<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:

0.000342

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.000417

AC XY:

AN XY:

74342

show subpopulations

African (AFR)

AF:

0.0000724

AC:

AN:

41438

American (AMR)

AF:

0.000981

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.0000941

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000456

AC:

AN:

68014

Other (OTH)

AF:

0.000957

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.520

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:

0.000524

Hom.:

Bravo

AF:

0.000563

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.000600

EpiControl

AF:

0.000891

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:6

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:2

May 20, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Oct 09, 2014

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

May 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

KCNT1: BP4, BP7, BS1 -

not specified

Benign:1

Oct 02, 2024

Athena Diagnostics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

Benign:1

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Inborn genetic diseases

Benign:1

Aug 15, 2016

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

Oct 11, 2019

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

BayesDel_noAF

Benign

-0.71

CADD

Benign

0.20

(source)

DANN

Benign

0.76

PhyloP100

-6.4

Mutation Taster

=99/1

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