rs587780455

Positions:

• chr12-51807116-A-G

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM2 PP2 PP3 PP5_Very_Strong

The NM_001330260.2(SCN8A):​c.5630A>G​(p.Asn1877Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SCN8A NM_001330260.2 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:13 U:2 O:1
• Conservation: PhyloP100: 9.32

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]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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 10.436 (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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.839
• PP5: Variant 12-51807116-A-G is Pathogenic according to our data. Variant chr12-51807116-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 130252.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SCN8A	NM_001330260.2	c.5630A>G	p.Asn1877Ser	missense_variant	27/27	ENST00000627620.5	NP_001317189.1
SCN8A	NM_014191.4	c.5630A>G	p.Asn1877Ser	missense_variant	27/27	ENST00000354534.11	NP_055006.1
SCN8A	NM_001177984.3	c.5507A>G	p.Asn1836Ser	missense_variant	26/26		NP_001171455.1
SCN8A	NM_001369788.1	c.5507A>G	p.Asn1836Ser	missense_variant	26/26		NP_001356717.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SCN8A	ENST00000354534.11	c.5630A>G	p.Asn1877Ser	missense_variant	27/27	1	NM_014191.4	ENSP00000346534.4
SCN8A	ENST00000627620.5	c.5630A>G	p.Asn1877Ser	missense_variant	27/27	5	NM_001330260.2	ENSP00000487583.2
SCN8A	ENST00000599343.5	c.5663A>G	p.Asn1888Ser	missense_variant	26/26	5		ENSP00000476447.3
SCN8A	ENST00000355133.7	c.5507A>G	p.Asn1836Ser	missense_variant	25/25	1		ENSP00000347255.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:13 Uncertain:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:4 Uncertain:2

Uncertain significance, flagged submission	clinical testing	Eurofins Ntd Llc (ga)	Jan 12, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Clinical Genetics Laboratory, Skane University Hospital Lund	May 27, 2022	- -
Uncertain significance, flagged submission	clinical testing	Genetic Services Laboratory, University of Chicago	Dec 06, 2013	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 25, 2021	Not observed in large population cohorts (Lek et al., 2016); The majority of missense variants in this gene are considered pathogenic (Stenson et al., 2014); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This substitution is predicted to be within the C-terminal cytoplasmic domain; This variant is associated with the following publications: (PMID: 29100083, 27210545, 30851583, 31164858, 32090326, 27875746, 27864847, 28923014, 30776697, 31487502, 32853054, 32040247) -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Feb 06, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Feb 01, 2022	- -

Seizures, benign familial infantile, 5 Pathogenic:3

Pathogenic, criteria provided, single submitter	research	University of British Columbia, BC Children's Hospital	Aug 30, 2023	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Oct 19, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Génétique des Maladies du Développement, Hospices Civils de Lyon	Dec 16, 2020	Absent from gnomAD. Predicted pathogenic. Genotype/phenotype correlation -

Developmental and epileptic encephalopathy, 13 Pathogenic:3

Likely pathogenic, no assertion criteria provided	clinical testing	Centre de Biologie Pathologie Génétique, Centre Hospitalier Universitaire de Lille	Jan 01, 2019	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Oct 19, 2020	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Mendelics	May 28, 2019	- -

Early infantile epileptic encephalopathy with suppression bursts Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 12, 2023

This missense change has been observed in individual(s) with early onset focal epileptic seizures without cognitive or neurological impairment (PMID: 27210545; Invitae). In at least one individual the variant was observed to be de novo. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 130252). 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 expected to disrupt SCN8A protein function. For these reasons, this variant has been classified as Pathogenic. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 1877 of the SCN8A protein (p.Asn1877Ser). -

Focal epilepsy Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Neurogenetics Laboratory - MEYER, AOU Meyer

Nov 16, 2016

- -

Seizure Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Diagnostic Laboratory, Strasbourg University Hospital

-

- -

Complex neurodevelopmental disorder Other:1

not provided, no classification provided

literature only

Channelopathy-Associated Epilepsy Research Center

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.75
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.80	D;.;.;.;.
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D;D;.;D;D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.84	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.8	M;.;.;.;M
PrimateAI	Uncertain	0.75	T
PROVEAN	Pathogenic	-4.7	D;D;.;.;.
REVEL	Pathogenic	0.78
Sift	Pathogenic	0.0	D;D;.;.;.
Sift4G	Benign	0.15	T;T;T;T;T
Polyphen		1.0	D;.;.;.;.
Vest4		0.69
MutPred		0.32		Gain of phosphorylation at N1877 (P = 0.0293);.;.;.;Gain of phosphorylation at N1877 (P = 0.0293);
MVP		0.97
MPC		2.0
ClinPred		0.99	D
GERP RS		5.0
Varity_R		0.78
gMVP		0.93

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

Other links and lift over

dbSNP: rs587780455; hg19: chr12-52200900;