9-135775387-C-T

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.2321C>T(p.Ala774Val) variant causes a missense change. The variant allele was found at a frequency of 0.0000254 in 1,611,112 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000026 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 4.88

Publications

0 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=0.06631321).

BP6

Variant 9-135775387-C-T is Benign according to our data. Variant chr9-135775387-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 412314.

BS1

Variant frequency is greater than expected in population amr. GnomAdExome4 allele frequency = 0.000026 (38/1458858) while in subpopulation AMR AF = 0.000586 (26/44348). AF 95% confidence interval is 0.00041. There are 0 homozygotes in GnomAdExome4. There are 17 alleles in the male GnomAdExome4 subpopulation. Median coverage is 31. This position passed quality control check.

BS2

High AC in GnomAdExome4 at 38 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.2321C>T	p.Ala774Val	missense_variant	Exon 20 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.2321C>T	p.Ala774Val	missense_variant	Exon 20 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152254

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000924

AC:

AN:

248892

AF XY:

0.0000669

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000658

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000882

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000260

AC:

AN:

1458858

Hom.:

Cov.:

AF XY:

0.0000234

AC XY:

AN XY:

725610

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33466

American (AMR)

AF:

0.000586

AC:

AN:

44348

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26104

East Asian (EAS)

AF:

0.00

AC:

AN:

39646

South Asian (SAS)

AF:

0.00

AC:

AN:

85232

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53386

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.0000108

AC:

AN:

1110606

Other (OTH)

AF:

0.00

AC:

AN:

60306

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

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:

0.0000197

AC:

AN:

152254

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74394

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41476

American (AMR)

AF:

0.0000654

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10630

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68036

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

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:

0.00

Hom.:

Bravo

AF:

0.0000302

ExAC

AF:

0.0000988

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Jul 06, 2016

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.A774V variant (also known as c.2321C>T), located in coding exon 20 of the KCNT1 gene, results from a C to T substitution at nucleotide position 2321. The alanine at codon 774 is replaced by valine, an amino acid with similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6503 samples (13006 alleles) with coverage at this position. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

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

Benign:1

Dec 17, 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

Benign

0.15

BayesDel_addAF

Benign

-0.26

BayesDel_noAF

Benign

-0.24

CADD

Uncertain

(source)

DANN

Benign

0.97

DEOGEN2

Benign

0.038

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

Eigen

Benign

-0.50

Eigen_PC

Benign

-0.33

FATHMM_MKL

Uncertain

0.94

LIST_S2

Benign

0.78

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

M_CAP

Benign

0.037

MetaRNN

Benign

0.066

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

MetaSVM

Benign

-0.89

MutationAssessor

Benign

-0.71

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

PhyloP100

4.9

PrimateAI

Uncertain

0.70

PROVEAN

Benign

-1.0

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

REVEL

Uncertain

0.32

Sift

Benign

0.92

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

Sift4G

Benign

0.29

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

Polyphen

0.0040

.;.;.;.;.;.;.;.;B;.

Vest4

0.53

MutPred

0.43

.;.;.;.;.;.;Gain of sheet (P = 0.0125);Gain of sheet (P = 0.0125);Gain of sheet (P = 0.0125);.;

MVP

0.65

MPC

0.65

ClinPred

0.049

GERP RS

3.6

Varity_R

0.20

gMVP

0.70

Mutation Taster

=22/78

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