rs769083534

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_020822.3(KCNT1):c.3671C>T(p.Ser1224Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000374 in 1,605,948 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

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

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

KCNT1
NM_020822.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 3.26

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.16709867).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNT1	NM_020822.3 linkuse as main transcript	c.3671C>T	p.Ser1224Phe	missense_variant	31/31	ENST00000371757.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNT1	ENST00000371757.7 linkuse as main transcript	c.3671C>T	p.Ser1224Phe	missense_variant	31/31	1	NM_020822.3	A2	Q5JUK3-3

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152166

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000415

AC:

AN:

241164

Hom.:

AF XY:

0.00

AC XY:

AN XY:

131522

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000904

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000138

AC:

AN:

1453782

Hom.:

Cov.:

AF XY:

0.00000276

AC XY:

AN XY:

723502

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

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:

0.0000166

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74324

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000151

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Aug 07, 2023

Variant summary: KCNT1 c.3671C>T (p.Ser1224Phe) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4.1e-06 in 241164 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.3671C>T in individuals affected with Developmental And Epileptic Encephalopathy, 14 and no experimental evidence demonstrating its impact on protein function have been reported. Two submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 16, 2023

This sequence change replaces serine, which is neutral and polar, with phenylalanine, which is neutral and non-polar, at codon 1224 of the KCNT1 protein (p.Ser1224Phe). This variant is present in population databases (rs769083534, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with KCNT1-related conditions. ClinVar contains an entry for this variant (Variation ID: 540576). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt KCNT1 protein function with a negative predictive value of 95%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 23, 2021

The c.3671C>T (p.S1224F) alteration is located in exon 31 (coding exon 31) of the KCNT1 gene. This alteration results from a C to T substitution at nucleotide position 3671, causing the serine (S) at amino acid position 1224 to be replaced by a phenylalanine (F). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.094

BayesDel_addAF

Benign

-0.20

BayesDel_noAF

Benign

-0.52

Cadd

Benign

Dann

Uncertain

0.99

Eigen

Benign

-0.19

Eigen_PC

Benign

-0.16

FATHMM_MKL

Benign

0.42

LIST_S2

Uncertain

0.93

D;D;D;D;D;D;D;D;D;D

M_CAP

Benign

0.069

MetaRNN

Benign

0.17

T;T;T;T;T;T;T;T;T;T

MetaSVM

Benign

-1.1

MutationTaster

Benign

0.97

N;N;N;N;N;N;N;N

PrimateAI

Benign

0.37

REVEL

Benign

0.069

Sift4G

Benign

0.16

T;T;T;T;T;T;T;T;T;T

Vest4

0.34

MVP

0.50

MPC

0.26

ClinPred

0.70

GERP RS

3.8

Varity_R

0.18

gMVP

0.40

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

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