2-166056503-A-G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_ModerateBP6_Moderate

The NM_001165963.4(SCN1A):c.384-3T>C variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000114 in 1,575,158 control chromosomes in the GnomAD database, with no homozygous occurrence. There is a variant allele frequency bias in the population database for this variant (GnomAdExome4), which may indicate mosaicism or somatic mutations in the reference population data. In-silico tool predicts a benign outcome for this variant. 2/2 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★).

Frequency

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

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

SCN1A
NM_001165963.4 splice_region, intron

Scores

Splicing: ADA: 0.01105

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: 3.52

Publications

0 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:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.23).

BP6

Variant 2-166056503-A-G is Benign according to our data. Variant chr2-166056503-A-G is described in ClinVar as Likely_benign. ClinVar VariationId is 461266.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN1A	NM_001165963.4 link	c.384-3T>C		splice_region_variant, intron_variant	Intron 5 of 28	ENST00000674923.1	NP_001159435.1

Ensembl

Gene	Transcript	HGVSc	Effect	Exon rank	TSL	MANE	Protein
SCN1A	ENST00000674923.1 link	c.384-3T>C	splice_region_variant, intron_variant	Intron 5 of 28		NM_001165963.4	ENSP00000501589.1
SCN1A	ENST00000303395.9 link	c.384-3T>C	splice_region_variant, intron_variant	Intron 4 of 27	5		ENSP00000303540.4
SCN1A	ENST00000375405.7 link	c.384-3T>C	splice_region_variant, intron_variant	Intron 2 of 25	5		ENSP00000364554.3
SCN1A	ENST00000409050.2 link	c.384-3T>C	splice_region_variant, intron_variant	Intron 4 of 27	5		ENSP00000386312.1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152116

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00000799

AC:

AN:

250418

AF XY:

0.00000739

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000885

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000112

AC:

AN:

1423042

Hom.:

Cov.:

AF XY:

0.00000985

AC XY:

AN XY:

710564

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:

32642

American (AMR)

AF:

0.0000224

AC:

AN:

44658

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25822

East Asian (EAS)

AF:

0.00

AC:

AN:

39442

South Asian (SAS)

AF:

0.00

AC:

AN:

85388

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53366

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5692

European-Non Finnish (NFE)

AF:

0.0000130

AC:

AN:

1076982

Other (OTH)

AF:

0.0000169

AC:

AN:

59050

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0000102982), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.394

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:

0.0000131

AC:

AN:

152116

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74302

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41442

American (AMR)

AF:

0.00

AC:

AN:

15238

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68000

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

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:

0.0000658

Hom.:

Bravo

AF:

0.0000227

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Developmental and epileptic encephalopathy

Benign:1

Feb 07, 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

0.43

BayesDel_noAF

Benign

-0.23

CADD

Benign

(source)

DANN

Benign

0.94

PhyloP100

3.5

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.011

SpliceAI score (max)

0.020

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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over