rs1553549461

Positions:

• chr2-166051734-A-G

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM2 PP2 PP3_Moderate PP5_Very_Strong

The NM_001165963.4(SCN1A):​c.949T>C​(p.Tyr317His) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SCN1A NM_001165963.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 6.60

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

Verdict is Pathogenic. Variant got 13 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SCN1A. . Gene score misZ 5.2206 (greater than the threshold 3.09). Trascript score misZ 7.6022 (greater than threshold 3.09). GenCC has associacion of gene with migraine, familial hemiplegic, 3, familial hemiplegic migraine, Dravet syndrome, malignant migrating partial seizures of infancy, generalized epilepsy with febrile seizures plus, myoclonic-astatic epilepsy, developmental and epileptic encephalopathy, developmental and epileptic encephalopathy, 6, familial or sporadic hemiplegic migraine, arthrogryposis, Lennox-Gastaut syndrome, generalized epilepsy with febrile seizures plus, type 2.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.871
• PP5: Variant 2-166051734-A-G is Pathogenic according to our data. Variant chr2-166051734-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 530489.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-166051734-A-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SCN1A	NM_001165963.4	c.949T>C	p.Tyr317His	missense_variant	9/29	ENST00000674923.1	NP_001159435.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SCN1A	ENST00000674923.1	c.949T>C	p.Tyr317His	missense_variant	9/29		NM_001165963.4	ENSP00000501589	P4
SCN1A-AS1	ENST00000651574.1	n.487+15604A>G		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 25, 2023

This sequence change replaces tyrosine, which is neutral and polar, with histidine, which is basic and polar, at codon 317 of the SCN1A protein (p.Tyr317His). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Dravet syndrome (PMID: 25459968). ClinVar contains an entry for this variant (Variation ID: 530489). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SCN1A protein function with a positive predictive value of 95%. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Mar 01, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.20
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.93	.;.;.;D;.;.;D;.;.;.
Eigen	Uncertain	0.42
Eigen_PC	Uncertain	0.47
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.86	D;D;D;D;.;D;.;.;D;D
M_CAP	Pathogenic	0.40	D
MetaRNN	Pathogenic	0.87	D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Benign	1.7	.;.;.;L;L;.;L;L;L;L
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.66	T
PROVEAN	Uncertain	-4.0	.;.;.;D;.;.;D;.;D;D
REVEL	Pathogenic	0.74
Sift	Uncertain	0.0010	.;.;.;D;.;.;D;.;D;D
Sift4G	Benign	0.23	.;.;.;T;.;.;T;.;T;T
Polyphen		1.0, 0.45	.;.;.;D;B;.;D;B;B;.
Vest4		0.86, 0.94, 0.92, 0.90
MutPred		0.71		Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);
MVP		0.93
MPC		1.9
ClinPred		0.99	D
GERP RS		5.4
Varity_R		0.56
gMVP		0.98

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

LitVar

Other links and lift over

dbSNP: rs1553549461; hg19: chr2-166908244;