chr9-135772897-C-A

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2BP4

The NM_020822.3(KCNT1):c.2191C>A(p.Gln731Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,212 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q731R) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 7.71

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: Uncertain_significance. The variant received 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.33911207).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.2191C>A	p.Gln731Lys	missense_variant	Exon 19 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.2191C>A	p.Gln731Lys	missense_variant	Exon 19 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152212

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1405848

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

695120

African (AFR)

AF:

0.00

AC:

AN:

32098

American (AMR)

AF:

0.00

AC:

AN:

36618

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

24948

East Asian (EAS)

AF:

0.00

AC:

AN:

36724

South Asian (SAS)

AF:

0.00

AC:

AN:

79696

European-Finnish (FIN)

AF:

0.00

AC:

AN:

47202

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5638

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1084776

Other (OTH)

AF:

0.00

AC:

AN:

58148

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152212

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74356

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41462

American (AMR)

AF:

0.00

AC:

AN:

15282

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:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68030

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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

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

Uncertain:1

Feb 20, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glutamine, which is neutral and polar, with lysine, which is basic and polar, at codon 731 of the KCNT1 protein (p.Gln731Lys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with KCNT1-related conditions. ClinVar contains an entry for this variant (Variation ID: 540583). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt KCNT1 protein function with a negative predictive value of 80%. 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. -

not provided

Uncertain:1

Aug 26, 2022

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.19

BayesDel_addAF

Uncertain

0.090

BayesDel_noAF

Benign

-0.11

CADD

Benign

(source)

DANN

Uncertain

0.97

DEOGEN2

Benign

0.077

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

Eigen

Benign

0.057

Eigen_PC

Benign

0.12

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.98

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

M_CAP

Uncertain

0.20

MetaRNN

Benign

0.34

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

MetaSVM

Uncertain

-0.11

MutationAssessor

Uncertain

2.2

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

PhyloP100

7.7

PrimateAI

Uncertain

0.66

PROVEAN

Benign

-1.9

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

REVEL

Uncertain

0.39

Sift

Benign

0.28

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

Sift4G

Benign

0.085

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

Polyphen

0.014

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

Vest4

0.54

MutPred

0.30

.;.;.;.;.;.;Gain of ubiquitination at Q712 (P = 0.0016);Gain of ubiquitination at Q712 (P = 0.0016);Gain of ubiquitination at Q712 (P = 0.0016);.;

MVP

0.74

MPC

0.81

ClinPred

0.91

GERP RS

3.9

Varity_R

0.44

gMVP

0.57

Mutation Taster

=65/35

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over