NM_020822.3:c.985C>T

Variant names:

Variant summary

Our verdict is Benign. Variant got -18 ACMG points: 0P and 18B. BP4_ModerateBP6_Very_StrongBS1BS2

The NM_020822.3(KCNT1):c.985C>T(p.Leu329Leu) variant causes a synonymous change. The variant allele was found at a frequency of 0.000144 in 1,613,202 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 0.00082 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000073 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 synonymous

Scores

Clinical Significance

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

Conservation

PhyloP100: 5.90

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 links:

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ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -18 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.41).

BP6

Variant 9-135759809-C-T is Benign according to our data. Variant chr9-135759809-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 241306.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-135759809-C-T is described in Lovd as [Likely_benign].

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00082 (125/152372) while in subpopulation AFR AF= 0.00289 (120/41590). AF 95% confidence interval is 0.00247. There are 0 homozygotes in gnomad4. There are 60 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.

BS2

High AC in GnomAd4 at 125 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3 link	c.985C>T	p.Leu329Leu	synonymous_variant	Exon 11 of 31	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.985C>T	p.Leu329Leu	synonymous_variant	Exon 11 of 31	1	NM_020822.3	ENSP00000360822.2		Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.000821

AC:

125

AN:

152254

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00289

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

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:

0.00

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.000228

AC:

AN:

250048

Hom.:

AF XY:

0.000185

AC XY:

AN XY:

135410

show subpopulations

Gnomad AFR exome

AF:

0.00334

Gnomad AMR exome

AF:

0.0000580

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.0000732

AC:

107

AN:

1460830

Hom.:

Cov.:

AF XY:

0.0000523

AC XY:

AN XY:

726718

show subpopulations

Gnomad4 AFR exome

AF:

0.00284

Gnomad4 AMR exome

AF:

0.0000896

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

9.00e-7

Gnomad4 OTH exome

AF:

0.000116

GnomAD4 genome

AF:

0.000820

AC:

125

AN:

152372

Hom.:

Cov.:

AF XY:

0.000805

AC XY:

AN XY:

74516

show subpopulations

Gnomad4 AFR

AF:

0.00289

Gnomad4 AMR

AF:

0.000261

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.000473

Alfa

AF:

0.000446

Hom.:

Bravo

AF:

0.00112

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:2

Jan 21, 2016

Eurofins Ntd Llc (ga)

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 02, 2017

GeneDx

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

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

Mar 21, 2016

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

Nov 11, 2019

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: 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

BayesDel_noAF

Benign

-0.41

CADD

Benign

DANN

Benign

0.75

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over