Genetic Variant NM_001330260.2:c.4122T>A (chr12-51786721-T-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.4122T>A(p.Thr1374Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00109 in 1,613,956 control chromosomes in the GnomAD database, including 12 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0049 ( 1 hom., cov: 32)

Exomes 𝑓: 0.00070 ( 11 hom. )

Consequence

SCN8A
NM_001330260.2 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:9

Conservation

PhyloP100: -3.37

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, STRONG Submitted by: ClinGen, PanelApp Australia
developmental and epileptic encephalopathy, 13
Inheritance: AD, AR Classification: DEFINITIVE, STRONG, LIMITED Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae), PanelApp Australia
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=-0.67).

BP6

Variant 12-51786721-T-A is Benign according to our data. Variant chr12-51786721-T-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 130246.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-3.37 with no splicing effect.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00489 (744/152300) while in subpopulation AFR AF = 0.0164 (682/41558). AF 95% confidence interval is 0.0154. There are 1 homozygotes in GnomAd4. There are 342 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High AC in GnomAd4 at 744 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	UniProt
SCN8A	NM_001330260.2	MANE Select	c.4122T>A	p.Thr1374Thr	synonymous	Exon 22 of 27	NP_001317189.1	Q9UQD0-2
SCN8A	NM_014191.4	MANE Plus Clinical	c.4122T>A	p.Thr1374Thr	synonymous	Exon 22 of 27	NP_055006.1	Q9UQD0-1
SCN8A	NM_001177984.3		c.3999T>A	p.Thr1333Thr	synonymous	Exon 21 of 26	NP_001171455.1	Q9UQD0-5

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
SCN8A	ENST00000354534.11	TSL:1 MANE Plus Clinical	c.4122T>A	p.Thr1374Thr	synonymous	Exon 22 of 27	ENSP00000346534.4	Q9UQD0-1
SCN8A	ENST00000627620.5	TSL:5 MANE Select	c.4122T>A	p.Thr1374Thr	synonymous	Exon 22 of 27	ENSP00000487583.2	Q9UQD0-2
SCN8A	ENST00000599343.5	TSL:5	c.4155T>A	p.Thr1385Thr	synonymous	Exon 21 of 26	ENSP00000476447.3	Q9UQD0-3

Frequencies

GnomAD3 genomes

AF:

0.00487

AC:

741

AN:

152182

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0164

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00295

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.000162

Gnomad OTH

AF:

0.00239

GnomAD2 exomes

AF:

0.00125

AC:

312

AN:

249010

AF XY:

0.000992

show subpopulations

Gnomad AFR exome

AF:

0.0154

Gnomad AMR exome

AF:

0.000928

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000284

Gnomad OTH exome

AF:

0.000827

GnomAD4 exome

AF:

0.000699

AC:

1021

AN:

1461656

Hom.:

Cov.:

AF XY:

0.000626

AC XY:

455

AN XY:

727102

show subpopulations

African (AFR)

AF:

0.0185

AC:

621

AN:

33478

American (AMR)

AF:

0.00119

AC:

AN:

44710

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000580

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.0000187

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00416

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000199

AC:

221

AN:

1111846

Other (OTH)

AF:

0.00159

AC:

AN:

60374

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.488

Heterozygous variant carriers

123

184

246

307

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

112

140

<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:

0.00489

AC:

744

AN:

152300

Hom.:

Cov.:

AF XY:

0.00459

AC XY:

342

AN XY:

74468

show subpopulations

African (AFR)

AF:

0.0164

AC:

682

AN:

41558

American (AMR)

AF:

0.00294

AC:

AN:

15300

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00340

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000162

AC:

AN:

68028

Other (OTH)

AF:

0.00237

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.503

Heterozygous variant carriers

110

147

184

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

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:

0.00116

Hom.:

Bravo

AF:

0.00548

Asia WGS

AF:

0.00202

AC:

AN:

3478

EpiCase

AF:

0.00

EpiControl

AF:

0.000474

ClinVar

ClinVar submissions

Significance:Benign/Likely benign

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

not specified (4)

not provided (2)

Cognitive impairment with or without cerebellar ataxia;C3281191:Developmental and epileptic encephalopathy, 13;C4310728:Seizures, benign familial infantile, 5;C5193056:Myoclonus, familial, 2 (1)

Developmental and epileptic encephalopathy (1)

Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.67

CADD

Benign

2.0

(source)

DANN

Benign

0.63

PhyloP100

-3.4

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

Computational scores

Splicing

Publications

Other links and lift over