rs202187894

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 1P and 6B. PP2BP4BP6BS2

The NM_001330260.2(SCN8A):​c.5506A>G​(p.Met1836Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000018 in 1,613,910 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M1836L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000018 ( 0 hom. )

Consequence

SCN8A
NM_001330260.2 missense

Scores

4
11
4

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:1

Conservation

PhyloP100: 9.32

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=0.41060057).
BP6
Variant 12-51806992-A-G is Benign according to our data. Variant chr12-51806992-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 530447.
BS2
High AC in GnomAdExome4 at 26 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SCN8ANM_001330260.2 linkc.5506A>G p.Met1836Val missense_variant Exon 27 of 27 ENST00000627620.5 NP_001317189.1 Q9UQD0-2Q6B4S4
SCN8ANM_014191.4 linkc.5506A>G p.Met1836Val missense_variant Exon 27 of 27 ENST00000354534.11 NP_055006.1 Q9UQD0-1
SCN8ANM_001177984.3 linkc.5383A>G p.Met1795Val missense_variant Exon 26 of 26 NP_001171455.1 Q9UQD0-5
SCN8ANM_001369788.1 linkc.5383A>G p.Met1795Val missense_variant Exon 26 of 26 NP_001356717.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
SCN8AENST00000354534.11 linkc.5506A>G p.Met1836Val missense_variant Exon 27 of 27 1 NM_014191.4 ENSP00000346534.4 Q9UQD0-1
SCN8AENST00000627620.5 linkc.5506A>G p.Met1836Val missense_variant Exon 27 of 27 5 NM_001330260.2 ENSP00000487583.2 Q9UQD0-2
SCN8AENST00000599343.5 linkc.5539A>G p.Met1847Val missense_variant Exon 26 of 26 5 ENSP00000476447.3 Q9UQD0-3
SCN8AENST00000355133.7 linkc.5383A>G p.Met1795Val missense_variant Exon 25 of 25 1 ENSP00000347255.4 Q9UQD0-5

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152214
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000131
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:
0.0000241
AC:
6
AN:
249452
AF XY:
0.00
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000868
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000553
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000177
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000178
AC:
26
AN:
1461696
Hom.:
0
Cov.:
33
AF XY:
0.0000179
AC XY:
13
AN XY:
727126
show subpopulations
African (AFR)
AF:
0.0000597
AC:
2
AN:
33480
American (AMR)
AF:
0.000112
AC:
5
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.0000504
AC:
2
AN:
39700
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53400
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000126
AC:
14
AN:
1111862
Other (OTH)
AF:
0.0000331
AC:
2
AN:
60370
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.500
Heterozygous variant carriers
0
3
5
8
10
13
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:
152214
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74358
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41458
American (AMR)
AF:
0.000131
AC:
2
AN:
15290
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5182
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4836
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10620
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:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.658
Heterozygous variant carriers
0
1
1
2
2
3
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:
0.0000264
ExAC
AF:
0.0000248
AC:
3
Asia WGS
AF:
0.000289
AC:
1
AN:
3478

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:3Benign:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:2
Aug 01, 2018
CeGaT Center for Human Genetics Tuebingen
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

May 13, 2020
Revvity Omics, Revvity
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not specified Uncertain:1
May 09, 2025
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: SCN8A c.5506A>G (p.Met1836Val) results in a conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change. The variant allele was found at a frequency of 2.4e-05 in 249452 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.5506A>G in individuals affected with Early Infantile Epileptic Encephalopathy 13 and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 530447). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Developmental and epileptic encephalopathy Benign:1
Sep 02, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.37
BayesDel_addAF
Pathogenic
0.34
D
BayesDel_noAF
Pathogenic
0.45
CADD
Uncertain
25
DANN
Benign
0.93
DEOGEN2
Uncertain
0.66
D;.;.;.;.
Eigen
Uncertain
0.26
Eigen_PC
Uncertain
0.40
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.87
D;D;.;D;D
M_CAP
Uncertain
0.22
D
MetaRNN
Benign
0.41
T;T;T;T;T
MetaSVM
Uncertain
0.63
D
MutationAssessor
Uncertain
2.2
M;.;.;.;M
PhyloP100
9.3
PrimateAI
Uncertain
0.74
T
PROVEAN
Uncertain
-3.5
D;D;.;.;.
REVEL
Pathogenic
0.78
Sift
Uncertain
0.023
D;D;.;.;.
Sift4G
Benign
0.14
T;T;T;T;T
Polyphen
0.070
B;.;.;.;.
Vest4
0.56
MutPred
0.51
Loss of sheet (P = 0.0817);.;.;.;Loss of sheet (P = 0.0817);
MVP
0.99
MPC
1.1
ClinPred
0.25
T
GERP RS
5.2
Varity_R
0.45
gMVP
0.95
Mutation Taster
=39/61
disease causing

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: rs202187894; hg19: chr12-52200776; API