12-51806992-A-T

Position:

chr12-51806992-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2PP2BP4

The NM_014191.4(SCN8A):c.5506A>T(p.Met1836Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,696 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M1836V) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

SCN8A
NM_014191.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 9.32

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 Uncertain_significance. Variant got 2 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 10.278 (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=0.38835078).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein
SCN8A	NM_001330260.2 linkuse as main transcript	c.5506A>T	p.Met1836Leu	missense_variant	27/27	ENST00000627620.5	NP_001317189.1
SCN8A	NM_014191.4 linkuse as main transcript	c.5506A>T	p.Met1836Leu	missense_variant	27/27	ENST00000354534.11	NP_055006.1
SCN8A	NM_001177984.3 linkuse as main transcript	c.5383A>T	p.Met1795Leu	missense_variant	26/26		NP_001171455.1
SCN8A	NM_001369788.1 linkuse as main transcript	c.5383A>T	p.Met1795Leu	missense_variant	26/26		NP_001356717.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SCN8A	ENST00000354534.11 linkuse as main transcript	c.5506A>T	p.Met1836Leu	missense_variant	27/27	1	NM_014191.4	ENSP00000346534	P4	Q9UQD0-1
SCN8A	ENST00000627620.5 linkuse as main transcript	c.5506A>T	p.Met1836Leu	missense_variant	27/27	5	NM_001330260.2	ENSP00000487583	A1	Q9UQD0-2

Frequencies

GnomAD3 genomes

AF:

0.00

AC:

AN:

152212

Hom.:

Cov.:

FAILED QC

Gnomad AFR

AF:

0.00

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

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461696

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727126

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:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000180

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

152212

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74358

Gnomad4 AFR

AF:

0.00

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:

0.0000239

Hom.:

Bravo

AF:

0.00000756

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000118

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

Jan 04, 2024

This sequence change replaces methionine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 1836 of the SCN8A protein (p.Met1836Leu). This variant is not present in population databases (gnomAD no frequency). 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: 1320728). 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

Jun 04, 2020

Not observed in large population cohorts (Lek et al., 2016); The majority of missense variants in this gene are considered pathogenic; In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.48

BayesDel_addAF

Pathogenic

0.38

BayesDel_noAF

Pathogenic

0.30

CADD

Uncertain

DANN

Benign

0.91

DEOGEN2

Uncertain

0.64

D;.;.;.;.

Eigen

Uncertain

0.30

Eigen_PC

Uncertain

0.42

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.85

D;D;.;D;D

M_CAP

Uncertain

0.11

MetaRNN

Benign

0.39

T;T;T;T;T

MetaSVM

Uncertain

0.60

MutationAssessor

Benign

1.9

L;.;.;.;L

MutationTaster

Benign

1.0

D;D

PrimateAI

Uncertain

0.79

PROVEAN

Uncertain

-2.7

D;D;.;.;.

REVEL

Pathogenic

0.72

Sift

Uncertain

0.0020

D;D;.;.;.

Sift4G

Benign

0.37

T;T;T;T;T

Polyphen

0.18

B;.;.;.;.

Vest4

0.44

MutPred

0.50

Loss of sheet (P = 0.0817);.;.;.;Loss of sheet (P = 0.0817);

MVP

0.99

MPC

1.0

ClinPred

0.85

GERP RS

5.2

Varity_R

0.67

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

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