chr9-135792141-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BS2

The NM_020822.3(KCNT1):c.3688C>T(p.Arg1230Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000165 in 1,453,622 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1230H) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.93

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:

LOC107987140 (HGNC:):

LOC107987140 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

BS2

High AC in GnomAdExome4 at 24 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.3688C>T	p.Arg1230Cys	missense_variant	Exon 31 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.3688C>T	p.Arg1230Cys	missense_variant	Exon 31 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.0000208

AC:

AN:

240888

AF XY:

0.00000761

show subpopulations

Gnomad AFR exome

AF:

0.0000636

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000181

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000165

AC:

AN:

1453622

Hom.:

Cov.:

AF XY:

0.0000152

AC XY:

AN XY:

723374

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33454

American (AMR)

AF:

0.00

AC:

AN:

44616

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26080

East Asian (EAS)

AF:

0.00

AC:

AN:

39658

South Asian (SAS)

AF:

0.0000465

AC:

AN:

86010

European-Finnish (FIN)

AF:

0.00

AC:

AN:

46190

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000171

AC:

AN:

1111566

Other (OTH)

AF:

0.00

AC:

AN:

60282

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.494

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

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

Uncertain:1

Jan 11, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

ClinVar contains an entry for this variant (Variation ID: 572792). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant has not been reported in the literature in individuals affected with KCNT1-related conditions. This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 1230 of the KCNT1 protein (p.Arg1230Cys). This variant is present in population databases (rs771068120, gnomAD 0.007%). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.27

BayesDel_addAF

Benign

-0.030

BayesDel_noAF

Benign

-0.10

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.23

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

Eigen

Benign

0.098

Eigen_PC

Benign

-0.070

FATHMM_MKL

Uncertain

0.85

LIST_S2

Pathogenic

0.98

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

M_CAP

Uncertain

0.27

MetaRNN

Uncertain

0.54

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

MetaSVM

Benign

-0.88

MutationAssessor

Benign

1.5

.;.;.;.;.;.;.;.;L;.

PhyloP100

1.9

PrimateAI

Uncertain

0.61

PROVEAN

Uncertain

-2.4

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

REVEL

Uncertain

0.36

Sift

Pathogenic

0.0

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

Sift4G

Pathogenic

0.0010

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

Vest4

0.70

MVP

0.57

MPC

0.49

ClinPred

0.38

GERP RS

2.7

Varity_R

0.27

gMVP

0.46

Mutation Taster

=72/28

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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chr9-135792141-C-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over