rs758311066

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_ModerateBP6BS2

The NM_020822.3(KCNT1):​c.3341G>A​(p.Arg1114Gln) variant causes a missense change. The variant allele was found at a frequency of 0.0000316 in 1,582,052 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1114W) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000028 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

3
6
10

Clinical Significance

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

Conservation

PhyloP100: 6.07

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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -7 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.17579317).
BP6
Variant 9-135786360-G-A is Benign according to our data. Variant chr9-135786360-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 473387.
BS2
High AC in GnomAd4 at 10 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
KCNT1NM_020822.3 linkc.3341G>A p.Arg1114Gln missense_variant Exon 29 of 31 ENST00000371757.7 NP_065873.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
KCNT1ENST00000371757.7 linkc.3341G>A p.Arg1114Gln missense_variant Exon 29 of 31 1 NM_020822.3 ENSP00000360822.2

Frequencies

GnomAD3 genomes
AF:
0.0000657
AC:
10
AN:
152164
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000482
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.000288
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000414
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000735
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000496
AC:
9
AN:
181304
AF XY:
0.0000401
show subpopulations
Gnomad AFR exome
AF:
0.000330
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:
0.0000540
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000280
AC:
40
AN:
1429888
Hom.:
0
Cov.:
36
AF XY:
0.0000282
AC XY:
20
AN XY:
708248
show subpopulations
African (AFR)
AF:
0.0000609
AC:
2
AN:
32850
American (AMR)
AF:
0.00
AC:
0
AN:
39432
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25452
East Asian (EAS)
AF:
0.00
AC:
0
AN:
38330
South Asian (SAS)
AF:
0.000145
AC:
12
AN:
82938
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
49366
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
4900
European-Non Finnish (NFE)
AF:
0.0000228
AC:
25
AN:
1097468
Other (OTH)
AF:
0.0000169
AC:
1
AN:
59152
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.499
Heterozygous variant carriers
0
3
5
8
10
13
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
10
AN:
152164
Hom.:
0
Cov.:
33
AF XY:
0.0000538
AC XY:
4
AN XY:
74328
show subpopulations
African (AFR)
AF:
0.0000482
AC:
2
AN:
41454
American (AMR)
AF:
0.00
AC:
0
AN:
15294
Ashkenazi Jewish (ASJ)
AF:
0.000288
AC:
1
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5178
South Asian (SAS)
AF:
0.000414
AC:
2
AN:
4830
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10626
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
314
European-Non Finnish (NFE)
AF:
0.0000735
AC:
5
AN:
67992
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
1
2
4
5
6
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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.:
0
Bravo
AF:
0.0000416
ExAC
AF:
0.0000533
AC:
6

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:1Benign:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Developmental and epileptic encephalopathy, 14;C3554306:Autosomal dominant nocturnal frontal lobe epilepsy 5 Uncertain:1
Jan 14, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 1114 of the KCNT1 protein (p.Arg1114Gln). This variant is present in population databases (rs758311066, gnomAD 0.02%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with clinical features of KCNT1-related conditions (internal data). ClinVar contains an entry for this variant (Variation ID: 473387). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) 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. -

Inborn genetic diseases Benign:1
Jun 28, 2024
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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.13
BayesDel_addAF
Benign
-0.23
T
BayesDel_noAF
Benign
-0.24
CADD
Uncertain
25
DANN
Pathogenic
1.0
DEOGEN2
Benign
0.098
.;.;.;.;.;.;.;.;T;.
Eigen
Uncertain
0.47
Eigen_PC
Uncertain
0.42
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Pathogenic
0.98
D;D;D;D;D;D;D;D;D;D
M_CAP
Uncertain
0.26
D
MetaRNN
Benign
0.18
T;T;T;T;T;T;T;T;T;T
MetaSVM
Benign
-0.81
T
MutationAssessor
Uncertain
2.3
.;.;.;.;.;.;.;.;M;.
PhyloP100
6.1
PrimateAI
Uncertain
0.53
T
PROVEAN
Benign
-1.6
.;.;N;.;.;N;.;.;N;N
REVEL
Benign
0.15
Sift
Uncertain
0.024
.;.;D;.;.;T;.;.;T;D
Sift4G
Benign
0.12
T;T;T;T;T;T;T;T;T;T
Vest4
0.36
MVP
0.48
MPC
0.11
ClinPred
0.14
T
GERP RS
4.8
Varity_R
0.18
gMVP
0.39
Mutation Taster
=57/43
polymorphism

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

Other links and lift over

dbSNP: rs758311066; hg19: chr9-138678206; API