rs1048609401

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 1P and 6B. PP2BP4_ModerateBS2

The NM_001330260.2(SCN8A):​c.1954A>G​(p.Ile652Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000193 in 1,602,574 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict 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. I652F) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 31)
Exomes 𝑓: 0.000019 ( 0 hom. )

Consequence

SCN8A
NM_001330260.2 missense

Scores

2
17

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.98

Publications

1 publications found
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 Gene-Disease associations (from GenCC):
  • complex neurodevelopmental disorder
    Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
  • developmental and epileptic encephalopathy, 13
    Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
  • cognitive impairment with or without cerebellar ataxia
    Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
  • seizures, benign familial infantile, 5
    Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
  • benign familial infantile epilepsy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • infantile convulsions and choreoathetosis
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • undetermined early-onset epileptic encephalopathy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • myoclonus, familial, 2
    Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -5 ACMG points.

PP2
Missense variant in the SCN8A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 213 curated pathogenic missense variants (we use a threshold of 10). The gene has 45 curated benign missense variants. Gene score misZ: 0.78755 (below the threshold of 3.09). Trascript score misZ: 10.436 (above the threshold of 3.09). GenCC associations: The gene is linked to myoclonus, familial, 2, developmental and epileptic encephalopathy, 13, undetermined early-onset epileptic encephalopathy, benign familial infantile epilepsy, complex neurodevelopmental disorder, seizures, benign familial infantile, 5, cognitive impairment with or without cerebellar ataxia, infantile convulsions and choreoathetosis.
BP4
Computational evidence support a benign effect (MetaRNN=0.075182796).
BS2
High AC in GnomAdExome4 at 28 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SCN8ANM_001330260.2 linkc.1954A>G p.Ile652Val missense_variant Exon 12 of 27 ENST00000627620.5 NP_001317189.1 Q9UQD0-2Q6B4S4
SCN8ANM_014191.4 linkc.1954A>G p.Ile652Val missense_variant Exon 12 of 27 ENST00000354534.11 NP_055006.1 Q9UQD0-1
SCN8ANM_001177984.3 linkc.1954A>G p.Ile652Val missense_variant Exon 12 of 26 NP_001171455.1 Q9UQD0-5
SCN8ANM_001369788.1 linkc.1954A>G p.Ile652Val missense_variant Exon 12 of 26 NP_001356717.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
SCN8AENST00000354534.11 linkc.1954A>G p.Ile652Val missense_variant Exon 12 of 27 1 NM_014191.4 ENSP00000346534.4 Q9UQD0-1
SCN8AENST00000627620.5 linkc.1954A>G p.Ile652Val missense_variant Exon 12 of 27 5 NM_001330260.2 ENSP00000487583.2 Q9UQD0-2
SCN8AENST00000599343.5 linkc.1954A>G p.Ile652Val missense_variant Exon 11 of 26 5 ENSP00000476447.3 Q9UQD0-3
SCN8AENST00000355133.7 linkc.1954A>G p.Ile652Val missense_variant Exon 11 of 25 1 ENSP00000347255.4 Q9UQD0-5

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152226
Hom.:
0
Cov.:
31
show subpopulations
Gnomad AFR
AF:
0.0000482
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
GnomAD2 exomes
AF:
0.00000425
AC:
1
AN:
235142
AF XY:
0.00000773
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000923
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000193
AC:
28
AN:
1450348
Hom.:
0
Cov.:
31
AF XY:
0.0000208
AC XY:
15
AN XY:
721954
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33472
American (AMR)
AF:
0.00
AC:
0
AN:
44720
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26134
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39696
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86254
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
42222
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000234
AC:
26
AN:
1111782
Other (OTH)
AF:
0.0000332
AC:
2
AN:
60300
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.502
Heterozygous variant carriers
0
3
6
8
11
14
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000197
AC:
3
AN:
152226
Hom.:
0
Cov.:
31
AF XY:
0.0000134
AC XY:
1
AN XY:
74370
show subpopulations
African (AFR)
AF:
0.0000482
AC:
2
AN:
41464
American (AMR)
AF:
0.00
AC:
0
AN:
15286
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5186
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4830
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10628
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68040
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.458
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.0000151
EpiCase
AF:
0.00
EpiControl
AF:
0.0000593

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Developmental and epileptic encephalopathy Uncertain:1
Dec 17, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 652 of the SCN8A protein (p.Ile652Val). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. 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: 573796). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) 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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.11
BayesDel_addAF
Benign
-0.070
T
BayesDel_noAF
Benign
-0.34
CADD
Benign
22
DANN
Benign
0.80
DEOGEN2
Benign
0.34
.;T;.;.;.;.;.
Eigen
Benign
-0.50
Eigen_PC
Benign
-0.36
FATHMM_MKL
Benign
0.67
D
LIST_S2
Uncertain
0.86
D;T;T;.;T;T;D
M_CAP
Benign
0.073
D
MetaRNN
Benign
0.075
T;T;T;T;T;T;T
MetaSVM
Benign
-0.36
T
MutationAssessor
Benign
-0.025
.;N;N;N;N;N;.
PhyloP100
2.0
PrimateAI
Uncertain
0.61
T
PROVEAN
Benign
0.030
.;N;N;N;.;.;.
REVEL
Benign
0.19
Sift
Benign
1.0
.;T;T;T;.;.;.
Sift4G
Benign
0.79
.;T;T;T;T;T;T
Polyphen
0.015, 0.60
.;B;.;.;P;.;.
Vest4
0.33, 0.36, 0.31, 0.33, 0.32
MutPred
0.35
Gain of sheet (P = 0.0477);Gain of sheet (P = 0.0477);Gain of sheet (P = 0.0477);Gain of sheet (P = 0.0477);Gain of sheet (P = 0.0477);Gain of sheet (P = 0.0477);.;
MVP
0.56
MPC
0.79
ClinPred
0.061
T
GERP RS
2.7
Varity_R
0.030
gMVP
0.56
Mutation Taster
=60/40
polymorphism

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

Other links and lift over

dbSNP: rs1048609401; hg19: chr12-52115648; API