Genetic Variant KCNT1:p.Arg538Arg (chr9-135770050-C-T) – ACMG Classification: Benign (-21 pts)

Variant summary

Our verdict is Benign. The variant received -21 ACMG points: 0P and 21B. BP4_StrongBP6_Very_StrongBP7BS1BS2

The NM_020822.3(KCNT1):c.1614C>T(p.Arg538Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000942 in 1,549,910 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.000079 ( 0 hom., cov: 34)

Exomes 𝑓: 0.000096 ( 2 hom. )

Consequence

KCNT1
NM_020822.3 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:5

Conservation

PhyloP100: -2.05

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: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
malignant migrating partial seizures of infancy
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, G2P
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 -21 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.75).

BP6

Variant 9-135770050-C-T is Benign according to our data. Variant chr9-135770050-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 383992.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-2.05 with no splicing effect.

BS1

Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.0000788 (12/152340) while in subpopulation SAS AF = 0.00124 (6/4834). AF 95% confidence interval is 0.00054. There are 0 homozygotes in GnomAd4. There are 6 alleles in the male GnomAd4 subpopulation. Median coverage is 34. This position passed quality control check.

BS2

High AC in GnomAd4 at 12 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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNT1	NM_020822.3	MANE Select	c.1614C>T	p.Arg538Arg	synonymous	Exon 16 of 31	NP_065873.2	Q5JUK3-3
	KCNT1	NM_001272003.2		c.1479C>T	p.Arg493Arg	synonymous	Exon 15 of 31	NP_001258932.1	Q5JUK3-4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
KCNT1	ENST00000371757.7	TSL:1 MANE Select	c.1614C>T	p.Arg538Arg	synonymous	Exon 16 of 31	ENSP00000360822.2	Q5JUK3-3
KCNT1	ENST00000460750.5	TSL:1	n.*1224C>T		non_coding_transcript_exon	Exon 16 of 32	ENSP00000418777.1	F8WC49
KCNT1	ENST00000460750.5	TSL:1	n.*1224C>T		3_prime_UTR	Exon 16 of 32	ENSP00000418777.1	F8WC49

Frequencies

GnomAD3 genomes

AF:

0.0000854

AC:

AN:

152222

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:

0.000965

Gnomad SAS

AF:

0.00124

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.000378

AC:

AN:

153406

AF XY:

0.000345

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000402

Gnomad ASJ exome

AF:

0.000120

Gnomad EAS exome

AF:

0.00290

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000173

Gnomad OTH exome

AF:

0.000920

GnomAD4 exome

AF:

0.0000959

AC:

134

AN:

1397570

Hom.:

Cov.:

AF XY:

0.000104

AC XY:

AN XY:

689524

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

31586

American (AMR)

AF:

0.0000278

AC:

AN:

35938

Ashkenazi Jewish (ASJ)

AF:

0.0000398

AC:

AN:

25144

East Asian (EAS)

AF:

0.000949

AC:

AN:

35816

South Asian (SAS)

AF:

0.000909

AC:

AN:

79212

European-Finnish (FIN)

AF:

0.00

AC:

AN:

48200

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4716

European-Non Finnish (NFE)

AF:

0.00000463

AC:

AN:

1079058

Other (OTH)

AF:

0.000363

AC:

AN:

57900

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.504

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

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:

0.0000788

AC:

AN:

152340

Hom.:

Cov.:

AF XY:

0.0000806

AC XY:

AN XY:

74480

show subpopulations

African (AFR)

AF:

0.0000240

AC:

AN:

41582

American (AMR)

AF:

0.00

AC:

AN:

15314

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000773

AC:

AN:

5172

South Asian (SAS)

AF:

0.00124

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68020

Other (OTH)

AF:

0.000473

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.533

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:

0.0000712

Hom.:

Bravo

AF:

0.0000831

Asia WGS

AF:

0.00144

AC:

AN:

3478

ClinVar

ClinVar submissions

Significance:Benign/Likely benign

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Autosomal dominant nocturnal frontal lobe epilepsy 5 (1)

Developmental and epileptic encephalopathy, 14 (1)

Developmental and epileptic encephalopathy, 14;C3554306:Autosomal dominant nocturnal frontal lobe epilepsy 5 (1)

KCNT1-related disorder (1)

not provided (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.75

CADD

Benign

5.0

(source)

DANN

Benign

0.92

PhyloP100

-2.1

Mutation Taster

=100/0

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

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

Computational scores

Splicing

Publications

Other links and lift over