NM_020822.3:c.851C>T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 4P and 10B. PM1PP3_ModerateBP6_ModerateBS1BS2

The NM_020822.3(KCNT1):c.851C>T(p.Thr284Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000185 in 1,612,744 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely benign (★). Synonymous variant affecting the same amino acid position (i.e. T284T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 34)

Exomes 𝑓: 0.00020 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: 7.58

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: Likely_benign. The variant received -6 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_020822.3

PP3

MetaRNN computational evidence supports a deleterious effect, 0.902

BP6

Variant 9-135758505-C-T is Benign according to our data. Variant chr9-135758505-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 473398.Status of the report is criteria_provided_single_submitter, 1 stars.

BS1

Variant frequency is greater than expected in population nfe. GnomAdExome4 allele frequency = 0.000198 (289/1460508) while in subpopulation NFE AF = 0.000256 (284/1111446). AF 95% confidence interval is 0.000231. There are 0 homozygotes in GnomAdExome4. There are 128 alleles in the male GnomAdExome4 subpopulation. Median coverage is 31. This position passed quality control check.

BS2

High AC in GnomAd4 at 10 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.851C>T	p.Thr284Met	missense_variant	Exon 10 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.851C>T	p.Thr284Met	missense_variant	Exon 10 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.0000657

AC:

AN:

152236

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000118

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000479

AC:

AN:

250746

AF XY:

0.0000664

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000471

Gnomad NFE exome

AF:

0.0000969

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000198

AC:

289

AN:

1460508

Hom.:

Cov.:

AF XY:

0.000176

AC XY:

128

AN XY:

726604

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33456

American (AMR)

AF:

0.00

AC:

AN:

44706

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86244

European-Finnish (FIN)

AF:

0.0000190

AC:

AN:

52688

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.000256

AC:

284

AN:

1111446

Other (OTH)

AF:

0.0000663

AC:

AN:

60376

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.474

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

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:

0.0000657

AC:

AN:

152236

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74378

show subpopulations

African (AFR)

AF:

0.0000482

AC:

AN:

41470

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5202

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000118

AC:

AN:

68036

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.435

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:

0.000120

Hom.:

Bravo

AF:

0.0000529

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000577

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.00

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

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

Benign:1

Sep 26, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.69

BayesDel_addAF

Pathogenic

0.36

BayesDel_noAF

Pathogenic

0.49

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.63

.;.;.;.;.;.;.;.;.;D;.

Eigen

Uncertain

0.65

Eigen_PC

Uncertain

0.60

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Pathogenic

0.99

D;D;D;D;D;D;D;D;D;D;D

M_CAP

Pathogenic

0.85

MetaRNN

Pathogenic

0.90

D;D;D;D;D;D;D;D;D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Uncertain

2.4

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

PhyloP100

7.6

PrimateAI

Uncertain

0.76

PROVEAN

Pathogenic

-5.4

.;.;D;D;D;.;.;.;.;D;D

REVEL

Uncertain

0.59

Sift

Pathogenic

0.0

.;.;D;D;D;.;.;.;.;D;D

Sift4G

Pathogenic

0.0

D;D;D;D;D;D;D;D;D;D;D

Polyphen

1.0

.;.;.;.;.;.;.;.;.;D;.

Vest4

0.92

MVP

0.95

MPC

1.7

ClinPred

0.88

GERP RS

4.7

Varity_R

0.82

gMVP

0.93

Mutation Taster

=21/79

disease causing

(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