12-51774312-G-A

Position:

chr12-51774312-G-A

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2BP4BS2

The NM_014191.4(SCN8A):c.3769G>A(p.Val1257Ile) variant causes a missense change. The variant allele was found at a frequency of 0.0000236 in 1,613,192 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 Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000023 ( 0 hom. )

Consequence

SCN8A
NM_014191.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 4.05

Variant links:

Genes affected

SCN8A (HGNC:10596): (sodium voltage-gated channel alpha subunit 8) This gene encodes a member of the sodium channel alpha subunit gene family. The encoded protein forms the ion pore region of the voltage-gated sodium channel. This protein is essential for the rapid membrane depolarization that occurs during the formation of the action potential in excitable neurons. Mutations in this gene are associated with cognitive disability, pancerebellar atrophy and ataxia. Alternate splicing results in multiple transcript variants.[provided by RefSeq, May 2010]

SCN8A links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SCN8A. . Gene score misZ 0.78755 (greater than the threshold 3.09). Trascript score misZ 10.278 (greater than threshold 3.09). GenCC has associacion of gene with myoclonus, familial, 2, infantile convulsions and choreoathetosis, cognitive impairment with or without cerebellar ataxia, undetermined early-onset epileptic encephalopathy, complex neurodevelopmental disorder, developmental and epileptic encephalopathy, 13, benign familial infantile epilepsy, seizures, benign familial infantile, 5.

BP4

Computational evidence support a benign effect (MetaRNN=0.35389808).

BS2

High AC in GnomAdExome4 at 34 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
SCN8A	NM_001330260.2 linkuse as main transcript	c.3769G>A	p.Val1257Ile	missense_variant	20/27	ENST00000627620.5
SCN8A	NM_014191.4 linkuse as main transcript	c.3769G>A	p.Val1257Ile	missense_variant	20/27	ENST00000354534.11
SCN8A	NM_001177984.3 linkuse as main transcript	c.3769G>A	p.Val1257Ile	missense_variant	20/26
SCN8A	NM_001369788.1 linkuse as main transcript	c.3769G>A	p.Val1257Ile	missense_variant	20/26

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SCN8A	ENST00000354534.11 linkuse as main transcript	c.3769G>A	p.Val1257Ile	missense_variant	20/27	1	NM_014191.4	P4	Q9UQD0-1
SCN8A	ENST00000627620.5 linkuse as main transcript	c.3769G>A	p.Val1257Ile	missense_variant	20/27	5	NM_001330260.2	A1	Q9UQD0-2

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152234

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000965

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.00

GnomAD3 exomes

AF:

0.0000280

AC:

AN:

250264

Hom.:

AF XY:

0.0000369

AC XY:

AN XY:

135360

show subpopulations

Gnomad AFR exome

AF:

0.0000623

Gnomad AMR exome

AF:

0.0000291

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:

0.0000353

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.0000233

AC:

AN:

1460958

Hom.:

Cov.:

AF XY:

0.0000275

AC XY:

AN XY:

726744

show subpopulations

Gnomad4 AFR exome

AF:

0.000149

Gnomad4 AMR exome

AF:

0.0000672

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000189

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152234

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74370

show subpopulations

Gnomad4 AFR

AF:

0.0000965

Gnomad4 AMR

AF:

0.00

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:

0.00

Alfa

AF:

0.0000658

Hom.:

Bravo

AF:

0.0000453

ExAC

AF:

0.0000412

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 07, 2023

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 1257 of the SCN8A protein (p.Val1257Ile). This variant is present in population databases (rs750829844, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with SCN8A-related conditions. ClinVar contains an entry for this variant (Variation ID: 207116). 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 SCN8A 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. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 30, 2015

The Val1257Ile missense change has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. It was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. This variant is a conservative substitution of one uncharged, non-polar amino acid for another. It alters a highly conserved residue between the S2 and S3 segments of the third transmembrane domain. In silico analysis is inconsistent with regard to the effect this variant may have on the protein structure/function. Therefore, based on the currently available information, it is unclear whether Val1257Ile is a disease-causing mutation or a rare benign variant. The variant is found in EPILEPSY panel(s). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Uncertain

0.014

BayesDel_noAF

Uncertain

-0.040

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.69

D;.;.;.;.

Eigen

Uncertain

0.23

Eigen_PC

Uncertain

0.36

FATHMM_MKL

Uncertain

0.96

LIST_S2

Benign

0.84

T;D;.;T;T

M_CAP

Uncertain

0.12

MetaRNN

Benign

0.35

T;T;T;T;T

MetaSVM

Uncertain

0.69

MutationAssessor

Benign

0.69

N;N;N;.;N

MutationTaster

Benign

1.0

D;D

PrimateAI

Uncertain

0.79

PROVEAN

Benign

-0.94

N;N;N;.;.

REVEL

Uncertain

0.56

Sift

Uncertain

0.025

D;T;T;.;.

Sift4G

Benign

0.070

T;T;T;T;T

Polyphen

0.83

P;.;.;.;.

Vest4

0.28

MVP

0.86

MPC

0.99

ClinPred

0.19

GERP RS

5.0

Varity_R

0.33

gMVP

0.78

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