Genetic Variant SCN1A:p.Leu1296Leu (chr2-166009833-C-T) – ACMG Classification: Benign (-9 pts)

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 2P and 11B. PM2BP4_ModerateBP6_Very_StrongBP7

The NM_001165963.4(SCN1A):c.3888G>A(p.Leu1296Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000311 in 1,606,056 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 (★★). Synonymous variant affecting the same amino acid position (i.e. L1296L) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

SCN1A
NM_001165963.4 synonymous

Scores

Clinical Significance

Likely benign criteria provided, multiple submitters, no conflicts B:2

Conservation

PhyloP100: 1.49

Publications

1 publications found

Variant links:

Genes affected

SCN1A (HGNC:10585): (sodium voltage-gated channel alpha subunit 1) Voltage-dependent sodium channels are heteromeric complexes that regulate sodium exchange between intracellular and extracellular spaces and are essential for the generation and propagation of action potentials in muscle cells and neurons. Each sodium channel is composed of a large pore-forming, glycosylated alpha subunit and two smaller beta subunits. This gene encodes a sodium channel alpha subunit, which has four homologous domains, each of which contains six transmembrane regions. Allelic variants of this gene are associated with generalized epilepsy with febrile seizures and epileptic encephalopathy. Alternative splicing results in multiple transcript variants. The RefSeq Project has decided to create four representative RefSeq records. Three of the transcript variants are supported by experimental evidence and the fourth contains alternate 5' untranslated exons, the exact combination of which have not been experimentally confirmed for the full-length transcript. [provided by RefSeq, Oct 2015]

SCN1A links:

SCN1A-AS1 (HGNC:54069): (SCN1A and SCN9A antisense RNA 1)

SCN1A-AS1 links:

LOC102724058 (HGNC:):

LOC102724058 links:

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ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -9 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.32).

BP6

Variant 2-166009833-C-T is Benign according to our data. Variant chr2-166009833-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 378515.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=1.49 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001165963.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
SCN1A	NM_001165963.4	MANE Select	c.3888G>A	p.Leu1296Leu	synonymous	Exon 23 of 29	NP_001159435.1
SCN1A	NM_001202435.3		c.3888G>A	p.Leu1296Leu	synonymous	Exon 22 of 28	NP_001189364.1
SCN1A	NM_001353948.2		c.3888G>A	p.Leu1296Leu	synonymous	Exon 21 of 27	NP_001340877.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
SCN1A	ENST00000674923.1	MANE Select	c.3888G>A	p.Leu1296Leu	synonymous	Exon 23 of 29	ENSP00000501589.1
SCN1A	ENST00000303395.9	TSL:5	c.3888G>A	p.Leu1296Leu	synonymous	Exon 22 of 28	ENSP00000303540.4
SCN1A	ENST00000375405.7	TSL:5	c.3855G>A	p.Leu1285Leu	synonymous	Exon 20 of 26	ENSP00000364554.3

Frequencies

GnomAD3 genomes

AF:

0.0000133

AC:

AN:

150776

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000664

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:

0.0000149

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000800

AC:

AN:

250088

AF XY:

0.00000740

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000291

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000886

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000206

AC:

AN:

1455280

Hom.:

Cov.:

AF XY:

0.00000276

AC XY:

AN XY:

724084

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33180

American (AMR)

AF:

0.0000225

AC:

AN:

44478

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25870

East Asian (EAS)

AF:

0.00

AC:

AN:

39440

South Asian (SAS)

AF:

0.00

AC:

AN:

86114

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53328

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5724

European-Non Finnish (NFE)

AF:

0.00000181

AC:

AN:

1107230

Other (OTH)

AF:

0.00

AC:

AN:

59916

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0338994), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.392

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:

0.0000133

AC:

AN:

150776

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

73598

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41208

American (AMR)

AF:

0.0000664

AC:

AN:

15068

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3436

East Asian (EAS)

AF:

0.00

AC:

AN:

5132

South Asian (SAS)

AF:

0.00

AC:

AN:

4814

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10572

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.0000149

AC:

AN:

67256

Other (OTH)

AF:

0.00

AC:

AN:

2066

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:1

Dec 15, 2016

GeneDx

Significance:Likely 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.

Developmental and epileptic encephalopathy

Benign:1

Dec 19, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely 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

-0.32

CADD

Benign

9.9

(source)

DANN

Benign

0.67

PhyloP100

1.5

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over