2-166073436-TG-TGG

Variant names:

• chr2-166073436-T-TG
• rs35595680
• NM_001165963.4:c.185dupC

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_001165963.4(SCN1A):​c.185dupC​(p.Phe63IlefsTer25) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 31)
• Consequence: SCN1A NM_001165963.4 frameshift
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.98
• Publications: 1 publications found

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

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN1A	NM_001165963.4	MANE Select	c.185dupC	p.Phe63IlefsTer25	frameshift	Exon 4 of 29	NP_001159435.1	P35498-1
	SCN1A	NM_001202435.3		c.185dupC	p.Phe63IlefsTer25	frameshift	Exon 3 of 28	NP_001189364.1	P35498-1
	SCN1A	NM_001353948.2		c.185dupC	p.Phe63IlefsTer25	frameshift	Exon 2 of 27	NP_001340877.1	P35498-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN1A	ENST00000674923.1	MANE Select	c.185dupC	p.Phe63IlefsTer25	frameshift	Exon 4 of 29	ENSP00000501589.1	P35498-1
	SCN1A	ENST00000303395.9	TSL:5	c.185dupC	p.Phe63IlefsTer25	frameshift	Exon 3 of 28	ENSP00000303540.4	P35498-1
	SCN1A	ENST00000375405.7	TSL:5	c.185dupC	p.Phe63IlefsTer25	frameshift	Exon 1 of 26	ENSP00000364554.3	P35498-2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		10

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

Other links and lift over

dbSNP: rs35595680; hg19: chr2-166929946;