rs368339692

Variant summary

Our verdict is Benign. The variant received -19 ACMG points: 1P and 20B. PP3BP4_StrongBP6_Very_StrongBS1BS2

The NM_020822.3(KCNT1):​c.3437G>A​(p.Arg1146His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000244 in 1,600,734 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1146C) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00016 ( 0 hom., cov: 33)
Exomes 𝑓: 0.00025 ( 1 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

6
8
5

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:7

Conservation

PhyloP100: 9.68

Publications

3 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 -19 ACMG points.

PP3
Multiple lines of computational evidence support a deleterious effect 6: AlphaMissense, Cadd, Dann, Eigen, FATHMM_MKL, phyloP100way_vertebrate [when BayesDel_addAF, max_spliceai, MetaRNN, MutationTaster was below the threshold]
BP4
Computational evidence support a benign effect (MetaRNN=0.052166134).
BP6
Variant 9-135786456-G-A is Benign according to our data. Variant chr9-135786456-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 473390.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
BS1
Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.000164 (25/152352) while in subpopulation SAS AF = 0.00373 (18/4832). AF 95% confidence interval is 0.00241. There are 0 homozygotes in GnomAd4. There are 16 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.
BS2
High AC in GnomAd4 at 25 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
KCNT1NM_020822.3 linkc.3437G>A p.Arg1146His missense_variant Exon 29 of 31 ENST00000371757.7 NP_065873.2 Q5JUK3-3

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
KCNT1ENST00000371757.7 linkc.3437G>A p.Arg1146His missense_variant Exon 29 of 31 1 NM_020822.3 ENSP00000360822.2 Q5JUK3-3

Frequencies

GnomAD3 genomes
AF:
0.000164
AC:
25
AN:
152234
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000482
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00372
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000735
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.000375
AC:
81
AN:
216266
AF XY:
0.000574
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000623
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000608
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000322
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.000253
AC:
366
AN:
1448382
Hom.:
1
Cov.:
36
AF XY:
0.000347
AC XY:
250
AN XY:
719946
show subpopulations
African (AFR)
AF:
0.0000608
AC:
2
AN:
32920
American (AMR)
AF:
0.0000697
AC:
3
AN:
43024
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25810
East Asian (EAS)
AF:
0.0000765
AC:
3
AN:
39200
South Asian (SAS)
AF:
0.00334
AC:
283
AN:
84786
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
50806
Middle Eastern (MID)
AF:
0.000195
AC:
1
AN:
5134
European-Non Finnish (NFE)
AF:
0.0000578
AC:
64
AN:
1107016
Other (OTH)
AF:
0.000168
AC:
10
AN:
59686
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.483
Heterozygous variant carriers
0
22
45
67
90
112
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
Variant carriers
0
10
20
30
40
50
<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:
0.000164
AC:
25
AN:
152352
Hom.:
0
Cov.:
33
AF XY:
0.000215
AC XY:
16
AN XY:
74500
show subpopulations
African (AFR)
AF:
0.0000481
AC:
2
AN:
41590
American (AMR)
AF:
0.00
AC:
0
AN:
15310
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5176
South Asian (SAS)
AF:
0.00373
AC:
18
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10632
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000735
AC:
5
AN:
68020
Other (OTH)
AF:
0.00
AC:
0
AN:
2116
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.513
Heterozygous variant carriers
0
3
6
9
12
15
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:
0.000139
Hom.:
0
Bravo
AF:
0.0000756
ESP6500AA
AF:
0.000235
AC:
1
ESP6500EA
AF:
0.00
AC:
0
ExAC
AF:
0.000354
AC:
42
Asia WGS
AF:
0.00115
AC:
4
AN:
3478

ClinVar

Significance: Benign/Likely benign
Submissions summary: Benign:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Benign:2
May 27, 2020
GeneDx
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Dec 01, 2024
CeGaT Center for Human Genetics Tuebingen
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

KCNT1: BS1 -

Developmental and epileptic encephalopathy, 14;C3554306:Autosomal dominant nocturnal frontal lobe epilepsy 5 Benign:1
Oct 15, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Inborn genetic diseases Benign:1
Oct 11, 2018
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. -

KCNT1-related disorder Benign:1
Mar 21, 2022
PreventionGenetics, part of Exact Sciences
Significance:Likely benign
Review Status:no assertion criteria provided
Collection Method:clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Developmental and epileptic encephalopathy, 14 Benign:1
Mar 15, 2022
Genome-Nilou Lab
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Autosomal dominant nocturnal frontal lobe epilepsy 5 Benign:1
Mar 15, 2022
Genome-Nilou Lab
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.59
BayesDel_addAF
Benign
-0.17
T
BayesDel_noAF
Uncertain
-0.030
CADD
Pathogenic
31
DANN
Pathogenic
1.0
DEOGEN2
Benign
0.36
.;.;.;.;.;.;.;.;T;.
Eigen
Pathogenic
0.72
Eigen_PC
Uncertain
0.61
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Pathogenic
1.0
D;D;D;D;D;D;D;D;D;D
M_CAP
Uncertain
0.27
D
MetaRNN
Benign
0.052
T;T;T;T;T;T;T;T;T;T
MetaSVM
Benign
-0.34
T
MutationAssessor
Uncertain
2.4
.;.;.;.;.;.;.;.;M;.
PhyloP100
9.7
PrimateAI
Uncertain
0.77
T
PROVEAN
Uncertain
-4.0
.;.;D;.;.;.;.;.;.;D
REVEL
Uncertain
0.47
Sift
Pathogenic
0.0
.;.;D;.;.;.;.;.;.;D
Sift4G
Uncertain
0.0020
D;D;D;D;D;D;D;D;D;D
Vest4
0.88
MVP
0.71
MPC
0.52
ClinPred
0.18
T
GERP RS
4.8
Varity_R
0.77
gMVP
0.56
Mutation Taster
=39/61
disease causing

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: rs368339692; hg19: chr9-138678302; COSMIC: COSV105045296; COSMIC: COSV105045296; API