NM_020822.3:c.1134C>T

Variant names:

Variant summary

Our verdict is Benign. The variant received -19 ACMG points: 0P and 19B. BP4_ModerateBP6_Very_StrongBP7BS1BS2

The NM_020822.3(KCNT1):c.1134C>T(p.Val378Val) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00108 in 1,613,578 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 Likely benign (★★).

Frequency

Genomes: 𝑓 0.00091 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0011 ( 1 hom. )

Consequence

KCNT1
NM_020822.3 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:11

Conservation

PhyloP100: 0.818

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 -19 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.37).

BP6

Variant 9-135765129-C-T is Benign according to our data. Variant chr9-135765129-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 211239.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=0.818 with no splicing effect.

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000906 (138/152316) while in subpopulation NFE AF = 0.00157 (107/68030). AF 95% confidence interval is 0.00133. There are 0 homozygotes in GnomAd4. There are 58 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High AC in GnomAd4 at 138 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.1134C>T	p.Val378Val	synonymous_variant	Exon 12 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.1134C>T	p.Val378Val	synonymous_variant	Exon 12 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.000907

AC:

138

AN:

152198

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000362

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000589

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000828

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00157

Gnomad OTH

AF:

0.00144

GnomAD2 exomes

AF:

0.000900

AC:

226

AN:

251034

AF XY:

0.000928

show subpopulations

Gnomad AFR exome

AF:

0.000247

Gnomad AMR exome

AF:

0.00101

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.00150

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00109

AC:

1597

AN:

1461262

Hom.:

Cov.:

AF XY:

0.00107

AC XY:

781

AN XY:

726920

show subpopulations

African (AFR)

AF:

0.0000597

AC:

AN:

33480

American (AMR)

AF:

0.000962

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26130

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.000429

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.0000756

AC:

AN:

52914

Middle Eastern (MID)

AF:

0.00121

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00130

AC:

1451

AN:

1111918

Other (OTH)

AF:

0.000878

AC:

AN:

60382

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.469

Heterozygous variant carriers

159

238

318

397

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

144

192

240

<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:

0.000906

AC:

138

AN:

152316

Hom.:

Cov.:

AF XY:

0.000779

AC XY:

AN XY:

74472

show subpopulations

African (AFR)

AF:

0.000361

AC:

AN:

41566

American (AMR)

AF:

0.000588

AC:

AN:

15298

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5178

South Asian (SAS)

AF:

0.000829

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00157

AC:

107

AN:

68030

Other (OTH)

AF:

0.00142

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.497

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:

0.00113

Hom.:

Bravo

AF:

0.000903

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.00147

EpiControl

AF:

0.00130

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:11

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:4

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Jun 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

KCNT1: BP4, BP7, BS1 -

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Jun 29, 2020

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Benign:2

Nov 15, 2016

Genetic Services Laboratory, University of Chicago

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Feb 01, 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

Jul 07, 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

Jun 20, 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). -

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

- -

Autosomal dominant nocturnal frontal lobe epilepsy 5

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

BayesDel_noAF

Benign

-0.37

CADD

Benign

7.5

(source)

DANN

Benign

0.71

PhyloP100

0.82

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