NM_020822.3:c.3178-12_3178-3delTGCCCTGCCC

Variant names:

Variant summary

Our verdict is Benign. The variant received -16 ACMG points: 0P and 16B. BP6_Very_StrongBS1BS2

The NM_020822.3(KCNT1):c.3178-12_3178-3delTGCCCTGCCC variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000185 in 1,548,246 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.00064 ( 0 hom., cov: 0)

Exomes 𝑓: 0.00014 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 splice_region, intron

Scores

Not classified

Clinical Significance

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

Conservation

PhyloP100: 1.02

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

KCNT1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -16 ACMG points.

BP6

Variant 9-135786170-CGCCCTGCCCT-C is Benign according to our data. Variant chr9-135786170-CGCCCTGCCCT-C is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 420320.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000637 (96/150636) while in subpopulation AFR AF = 0.00189 (77/40750). AF 95% confidence interval is 0.00155. There are 0 homozygotes in GnomAd4. There are 53 alleles in the male GnomAd4 subpopulation. Median coverage is 0. This position passed quality control check.

BS2

High AC in GnomAd4 at 96 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.3178-12_3178-3delTGCCCTGCCC		splice_region_variant, intron_variant	Intron 28 of 30	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.3178-12_3178-3delTGCCCTGCCC		splice_region_variant, intron_variant	Intron 28 of 30	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.000638

AC:

AN:

150522

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00190

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000592

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:

0.000133

Gnomad OTH

AF:

0.000484

GnomAD2 exomes

AF:

0.000213

AC:

AN:

197052

AF XY:

0.000228

show subpopulations

Gnomad AFR exome

AF:

0.00145

Gnomad AMR exome

AF:

0.000220

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000538

Gnomad NFE exome

AF:

0.000218

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000136

AC:

190

AN:

1397610

Hom.:

AF XY:

0.000139

AC XY:

AN XY:

696448

show subpopulations

African (AFR)

AF:

0.00206

AC:

AN:

30558

American (AMR)

AF:

0.000180

AC:

AN:

38862

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25146

East Asian (EAS)

AF:

0.00

AC:

AN:

38612

South Asian (SAS)

AF:

0.0000732

AC:

AN:

81930

European-Finnish (FIN)

AF:

0.0000396

AC:

AN:

50460

Middle Eastern (MID)

AF:

0.000179

AC:

AN:

5596

European-Non Finnish (NFE)

AF:

0.0000927

AC:

AN:

1068454

Other (OTH)

AF:

0.000207

AC:

AN:

57992

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

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:

0.000637

AC:

AN:

150636

Hom.:

Cov.:

AF XY:

0.000720

AC XY:

AN XY:

73582

show subpopulations

African (AFR)

AF:

0.00189

AC:

AN:

40750

American (AMR)

AF:

0.000592

AC:

AN:

15210

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5068

South Asian (SAS)

AF:

0.00

AC:

AN:

4744

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10472

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000133

AC:

AN:

67644

Other (OTH)

AF:

0.000479

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.519

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.:

365

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

Oct 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

KCNT1: BP4, BS1 -

Feb 12, 2024

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

See Variant Classification Assertion Criteria. -

not specified

Benign:1

Apr 29, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: KCNT1 c.3178-12_3178-3del10 alters non-conserved nucleotides located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Consensus agreement among computation tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00021 in 197052 control chromosomes. To our knowledge, no occurrence of c.3178-12_3178-3del10 in individuals affected with Developmental And Epileptic Encephalopathy, 14 and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 420320). Based on the evidence outlined above, the variant was classified as Likely Benign. -

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

Benign:1

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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. -

Developmental and epileptic encephalopathy, 14

Benign:1

Mar 15, 2022

Genome-Nilou Lab

Significance:Likely 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:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

1.0

Mutation Taster

=100/0

polymorphism

(source)

Splicing

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