rs121918800

Variant names:

• chr2-166013757-C-A
• NM_001165963.4:c.3692G>T

Your query was ambiguous. Multiple possible variants found:

• chr2-166013757-C-A
• chr2-166013757-C-G
• chr2-166013757-C-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5_Moderate

The NM_001165963.4(SCN1A):​c.3692G>T​(p.Ser1231Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S1231T) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SCN1A NM_001165963.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.90

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)

LOC102724058 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM1: In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_001165963.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-166013757-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2972409.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant in the SCN1A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 848 curated pathogenic missense variants (we use a threshold of 10). The gene has 89 curated benign missense variants. Gene score misZ: 5.2206 (above the threshold of 3.09). Trascript score misZ: 7.6022 (above the threshold of 3.09). GenCC associations: The gene is linked to 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, 0.931
• PP5: Variant 2-166013757-C-A is Pathogenic according to our data. Variant chr2-166013757-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2034846.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	c.3692G>T	p.Ser1231Ile	missense_variant	Exon 21 of 29	ENST00000674923.1	NP_001159435.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN1A	ENST00000674923.1	c.3692G>T	p.Ser1231Ile	missense_variant	Exon 21 of 29		NM_001165963.4	ENSP00000501589.1
SCN1A	ENST00000303395.9	c.3692G>T	p.Ser1231Ile	missense_variant	Exon 20 of 28	5		ENSP00000303540.4
SCN1A	ENST00000375405.7	c.3659G>T	p.Ser1220Ile	missense_variant	Exon 18 of 26	5		ENSP00000364554.3
SCN1A	ENST00000409050.1	c.3608G>T	p.Ser1203Ile	missense_variant	Exon 18 of 26	5		ENSP00000386312.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts Pathogenic:1

Oct 21, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces serine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 1231 of the SCN1A protein (p.Ser1231Ile). This variant has not been reported in the literature in individuals affected with SCN1A-related conditions. This variant is not present in population databases (gnomAD no frequency). 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. 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. This variant disrupts the p.S1231 amino acid residue in SCN1A. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 16458823). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. -

SCN1A-related disorder Pathogenic:1

Oct 23, 2023

PreventionGenetics, part of Exact Sciences

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The SCN1A c.3692G>T variant is predicted to result in the amino acid substitution p.Ser1231Ile. To our knowledge, this exact variant has not been reported in any affected individuals in the literature, or in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Two alternate missense changes at the same amino acid position have been reported as de novo findings in patients with autosomal dominant SCN1A-related disorders (p.Ser1231Thr; p.Ser1231Arg; Kearney et al. 2006. PubMed ID: 16458823; Fujiwara et al. 2003. PubMed ID: 12566275). This variant is interpreted as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	.;.;.;D;.;.;D;.;.;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.97	D;D;D;D;.;D;.;.;D;D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.93	D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.7	.;.;.;H;.;.;H;.;.;.
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-5.7	.;.;.;D;.;.;D;.;D;D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	.;.;.;D;.;.;D;.;D;D
Sift4G	Pathogenic	0.0	.;.;.;D;.;.;D;.;D;D
Polyphen		1.0, 0.99	.;.;.;D;D;.;D;D;D;.
Vest4		0.96, 0.92, 0.94, 0.96
MutPred		0.60		.;Gain of helix (P = 0.027);.;Gain of helix (P = 0.027);.;.;Gain of helix (P = 0.027);.;.;.;
MVP		1.0
MPC		1.9
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.93
gMVP		0.99

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-166870267;