Genetic Variant SCN8A:p.Gln1867Gln (chr12-51807087-G-A) – ACMG Classification: Benign (-21 pts)

Variant summary

Our verdict is Benign. The variant received -21 ACMG points: 0P and 21B. BP4_StrongBP6_Very_StrongBP7BS1BS2

The NM_001330260.2(SCN8A):c.5601G>A(p.Gln1867Gln) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00018 in 1,614,050 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 Likely benign (★★).

Frequency

Genomes: 𝑓 0.00068 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00013 ( 0 hom. )

Consequence

SCN8A
NM_001330260.2 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:7

Conservation

PhyloP100: 0.482

Publications

0 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

SCN8A links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -21 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.53).

BP6

Variant 12-51807087-G-A is Benign according to our data. Variant chr12-51807087-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 207102.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=0.482 with no splicing effect.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000676 (103/152340) while in subpopulation AFR AF = 0.00207 (86/41578). AF 95% confidence interval is 0.00172. There are 0 homozygotes in GnomAd4. There are 48 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High AC in GnomAd4 at 103 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001330260.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
SCN8A	NM_001330260.2	MANE Select	c.5601G>A	p.Gln1867Gln	synonymous	Exon 27 of 27	NP_001317189.1
SCN8A	NM_014191.4	MANE Plus Clinical	c.5601G>A	p.Gln1867Gln	synonymous	Exon 27 of 27	NP_055006.1
SCN8A	NM_001177984.3		c.5478G>A	p.Gln1826Gln	synonymous	Exon 26 of 26	NP_001171455.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
SCN8A	ENST00000354534.11	TSL:1 MANE Plus Clinical	c.5601G>A	p.Gln1867Gln	synonymous	Exon 27 of 27	ENSP00000346534.4
SCN8A	ENST00000627620.5	TSL:5 MANE Select	c.5601G>A	p.Gln1867Gln	synonymous	Exon 27 of 27	ENSP00000487583.2
SCN8A	ENST00000599343.5	TSL:5	c.5634G>A	p.Gln1878Gln	synonymous	Exon 26 of 26	ENSP00000476447.3

Frequencies

GnomAD3 genomes

AF:

0.000677

AC:

103

AN:

152222

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00207

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000393

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.0127

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00143

GnomAD2 exomes

AF:

0.000225

AC:

AN:

249142

AF XY:

0.000207

show subpopulations

Gnomad AFR exome

AF:

0.00213

Gnomad AMR exome

AF:

0.000232

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000124

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.000129

AC:

188

AN:

1461710

Hom.:

Cov.:

AF XY:

0.000118

AC XY:

AN XY:

727138

show subpopulations

African (AFR)

AF:

0.00212

AC:

AN:

33480

American (AMR)

AF:

0.000380

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53402

Middle Eastern (MID)

AF:

0.00121

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000630

AC:

AN:

1111868

Other (OTH)

AF:

0.000364

AC:

AN:

60374

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.487

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<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:

0.000676

AC:

103

AN:

152340

Hom.:

Cov.:

AF XY:

0.000644

AC XY:

AN XY:

74492

show subpopulations

African (AFR)

AF:

0.00207

AC:

AN:

41578

American (AMR)

AF:

0.000392

AC:

AN:

15304

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.0136

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68032

Other (OTH)

AF:

0.00142

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.505

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<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:

0.000346

Hom.:

Bravo

AF:

0.000824

Asia WGS

AF:

0.000577

AC:

AN:

3478

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:3

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

Mar 08, 2018

Athena Diagnostics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

not specified

Benign:2

Oct 14, 2014

GeneDx

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease.

Mar 12, 2018

Eurofins Ntd Llc (ga)

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Inborn genetic diseases

Benign:1

Feb 08, 2017

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

Developmental and epileptic encephalopathy

Benign:1

Jan 23, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.53

CADD

Benign

6.4

(source)

DANN

Benign

0.91

PhyloP100

0.48

Mutation Taster

=100/0

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over