NM_020822.3:c.2220C>T

Variant names:

Variant summary

Our verdict is Benign. The variant received -11 ACMG points: 0P and 11B. BP4_StrongBP6_ModerateBP7BS2

The NM_020822.3(KCNT1):c.2220C>T(p.Asp740Asp) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000211 in 1,518,880 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 Likely benign (★).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000020 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 synonymous

Scores

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: -4.50

Publications

6 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 -11 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.57).

BP6

Variant 9-135772926-C-T is Benign according to our data. Variant chr9-135772926-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 700074.Status of the report is criteria_provided_single_submitter, 1 stars.

BP7

Synonymous conserved (PhyloP=-4.49 with no splicing effect.

BS2

High AC in GnomAdExome4 at 28 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020822.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNT1	NM_020822.3	MANE Select	c.2220C>T	p.Asp740Asp	synonymous	Exon 19 of 31	NP_065873.2
	KCNT1	NM_001272003.2		c.2085C>T	p.Asp695Asp	synonymous	Exon 18 of 31	NP_001258932.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNT1	ENST00000371757.7	TSL:1 MANE Select	c.2220C>T	p.Asp740Asp	synonymous	Exon 19 of 31	ENSP00000360822.2
KCNT1	ENST00000460750.5	TSL:1	n.*1830C>T		non_coding_transcript_exon	Exon 19 of 32	ENSP00000418777.1
KCNT1	ENST00000460750.5	TSL:1	n.*1830C>T		3_prime_UTR	Exon 19 of 32	ENSP00000418777.1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152182

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:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

126108

AF XY:

0.0000295

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000969

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000194

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000205

AC:

AN:

1366580

Hom.:

Cov.:

AF XY:

0.0000164

AC XY:

AN XY:

672564

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

30840

American (AMR)

AF:

0.00

AC:

AN:

30714

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

22932

East Asian (EAS)

AF:

0.0000281

AC:

AN:

35610

South Asian (SAS)

AF:

0.0000135

AC:

AN:

73922

European-Finnish (FIN)

AF:

0.00

AC:

AN:

43098

Middle Eastern (MID)

AF:

0.000184

AC:

AN:

5446

European-Non Finnish (NFE)

AF:

0.0000234

AC:

AN:

1067472

Other (OTH)

AF:

0.00

AC:

AN:

56546

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.459

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:

0.0000263

AC:

AN:

152300

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74452

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41572

American (AMR)

AF:

0.00

AC:

AN:

15304

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000194

AC:

AN:

5166

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10630

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68020

Other (OTH)

AF:

0.00

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.513

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.:

Bravo

AF:

0.0000189

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

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

Benign:1

Feb 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.57

CADD

Benign

0.50

(source)

DANN

Benign

0.80

PhyloP100

-4.5

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.070

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over