Genetic Variant NM_020822.3:c.2166G>A (chr9-135772872-G-A) – 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.2166G>A(p.Leu722Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000553 in 1,556,888 control chromosomes in the GnomAD database, including 4 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.00033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00058 ( 4 hom. )

Consequence

KCNT1
NM_020822.3 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:9

Conservation

PhyloP100: 0.663

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: 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=-0.53).

BP6

Variant 9-135772872-G-A is Benign according to our data. Variant chr9-135772872-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 385228.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=0.663 with no splicing effect.

BS1

Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.000335 (51/152346) while in subpopulation SAS AF = 0.00187 (9/4820). AF 95% confidence interval is 0.000974. There are 0 homozygotes in GnomAd4. There are 26 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High AC in GnomAd4 at 51 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.2166G>A	p.Leu722Leu	synonymous	Exon 19 of 31	NP_065873.2	Q5JUK3-3
	KCNT1	NM_001272003.2		c.2031G>A	p.Leu677Leu	synonymous	Exon 18 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.2166G>A	p.Leu722Leu	synonymous	Exon 19 of 31	ENSP00000360822.2	Q5JUK3-3
KCNT1	ENST00000460750.5	TSL:1	n.*1776G>A		non_coding_transcript_exon	Exon 19 of 32	ENSP00000418777.1	F8WC49
KCNT1	ENST00000460750.5	TSL:1	n.*1776G>A		3_prime_UTR	Exon 19 of 32	ENSP00000418777.1	F8WC49

Frequencies

GnomAD3 genomes

AF:

0.000335

AC:

AN:

152228

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000193

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00187

Gnomad FIN

AF:

0.0000941

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000470

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000550

AC:

AN:

163616

AF XY:

0.000566

show subpopulations

Gnomad AFR exome

AF:

0.0000991

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000803

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000630

Gnomad OTH exome

AF:

0.000448

GnomAD4 exome

AF:

0.000577

AC:

810

AN:

1404542

Hom.:

Cov.:

AF XY:

0.000621

AC XY:

431

AN XY:

693990

show subpopulations

African (AFR)

AF:

0.0000623

AC:

AN:

32106

American (AMR)

AF:

0.00

AC:

AN:

36408

Ashkenazi Jewish (ASJ)

AF:

0.0000399

AC:

AN:

25036

East Asian (EAS)

AF:

0.0000273

AC:

AN:

36590

South Asian (SAS)

AF:

0.00199

AC:

159

AN:

79742

European-Finnish (FIN)

AF:

0.000105

AC:

AN:

47530

Middle Eastern (MID)

AF:

0.00161

AC:

AN:

5594

European-Non Finnish (NFE)

AF:

0.000547

AC:

593

AN:

1083434

Other (OTH)

AF:

0.000688

AC:

AN:

58102

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

122

163

204

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

104

130

<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:

0.000335

AC:

AN:

152346

Hom.:

Cov.:

AF XY:

0.000349

AC XY:

AN XY:

74494

show subpopulations

African (AFR)

AF:

0.000192

AC:

AN:

41580

American (AMR)

AF:

0.0000653

AC:

AN:

15310

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.00187

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.0000941

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000470

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

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:

0.000448

Hom.:

Bravo

AF:

0.000310

ClinVar

ClinVar submissions

Significance:Benign/Likely benign

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (5)

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)

Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.53

CADD

Benign

(source)

DANN

Benign

0.93

PhyloP100

0.66

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