12-51706554-C-T

Position:

chr12-51706554-C-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PP2BS2

The ENST00000354534.11(SCN8A):c.1474C>T(p.Arg492Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000249 in 1,607,420 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R492H) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000026 ( 0 hom. )

Consequence

SCN8A
ENST00000354534.11 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 1.12

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 -3 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.

BS2

High AC in GnomAdExome4 at 38 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein
SCN8A	NM_001330260.2 linkuse as main transcript	c.1474C>T	p.Arg492Cys	missense_variant	11/27	ENST00000627620.5	NP_001317189.1
SCN8A	NM_014191.4 linkuse as main transcript	c.1474C>T	p.Arg492Cys	missense_variant	11/27	ENST00000354534.11	NP_055006.1
SCN8A	NM_001177984.3 linkuse as main transcript	c.1474C>T	p.Arg492Cys	missense_variant	11/26		NP_001171455.1
SCN8A	NM_001369788.1 linkuse as main transcript	c.1474C>T	p.Arg492Cys	missense_variant	11/26		NP_001356717.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SCN8A	ENST00000354534.11 linkuse as main transcript	c.1474C>T	p.Arg492Cys	missense_variant	11/27	1	NM_014191.4	ENSP00000346534	P4	Q9UQD0-1
SCN8A	ENST00000627620.5 linkuse as main transcript	c.1474C>T	p.Arg492Cys	missense_variant	11/27	5	NM_001330260.2	ENSP00000487583	A1	Q9UQD0-2

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

151942

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000421

AC:

AN:

237448

Hom.:

AF XY:

0.0000389

AC XY:

AN XY:

128514

show subpopulations

Gnomad AFR exome

AF:

0.0000688

Gnomad AMR exome

AF:

0.0000600

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000345

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000468

Gnomad OTH exome

AF:

0.000172

GnomAD4 exome

AF:

0.0000261

AC:

AN:

1455360

Hom.:

Cov.:

AF XY:

0.0000207

AC XY:

AN XY:

723260

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000685

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000118

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000307

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000132

AC:

AN:

152060

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74324

show subpopulations

Gnomad4 AFR

AF:

0.0000241

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:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000868

Hom.:

ExAC

AF:

0.0000331

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 12, 2017

The p.R492C variant (also known as c.1474C>T), located in coding exon 10 of the SCN8A gene, results from a C to T substitution at nucleotide position 1474. The arginine at codon 492 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Early infantile epileptic encephalopathy with suppression bursts

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 21, 2023

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 492 of the SCN8A protein (p.Arg492Cys). This variant is present in population databases (rs576362165, gnomAD 0.006%). 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: 589221). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on SCN8A protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.69

BayesDel_addAF

Uncertain

0.14

BayesDel_noAF

Pathogenic

0.15

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.87

.;D;.;.;.;.;.

Eigen

Uncertain

0.60

Eigen_PC

Uncertain

0.50

FATHMM_MKL

Uncertain

0.91

LIST_S2

Pathogenic

0.98

D;D;D;.;D;D;D

M_CAP

Pathogenic

0.63

MetaRNN

Uncertain

0.62

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

MetaSVM

Pathogenic

0.86

MutationAssessor

Pathogenic

2.9

.;M;M;M;M;M;.

MutationTaster

Benign

1.0

D;D;D

PrimateAI

Pathogenic

0.87

PROVEAN

Pathogenic

-6.5

.;D;D;D;.;.;.

REVEL

Pathogenic

0.67

Sift

Pathogenic

0.0

.;D;D;D;.;.;.

Sift4G

Uncertain

0.0060

.;D;D;D;D;D;D

Polyphen

1.0

.;D;.;.;D;.;.

Vest4

0.61, 0.60, 0.66, 0.61, 0.58

MutPred

0.26

Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);.;

MVP

0.92

MPC

2.4

ClinPred

0.70

GERP RS

4.2

Varity_R

0.71

gMVP

0.64

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