NM_001165963.4:c.3734G>A

Variant names:

• chr2-166012254-C-T
• rs121917912
• NM_001165963.4:c.3734G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 13P and 4B. PM1 PP2 PP3_Moderate PP5_Very_Strong BS2

The NM_001165963.4(SCN1A):​c.3734G>A​(p.Arg1245Gln) variant causes a missense change. The variant allele was found at a frequency of 0.00000435 in 1,609,000 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: SCN1A NM_001165963.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6 O:1
• Conservation: PhyloP100: 6.12
• Publications: 9 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)

LOC102724058 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 6 uncertain in NM_001165963.4
• 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 familial or sporadic hemiplegic migraine, myoclonic-astatic epilepsy, arthrogryposis, Dravet syndrome, malignant migrating partial seizures of infancy, generalized epilepsy with febrile seizures plus, type 2, migraine, familial hemiplegic, 3, developmental and epileptic encephalopathy, 6A, familial hemiplegic migraine, generalized epilepsy with febrile seizures plus, genetic developmental and epileptic encephalopathy, Lennox-Gastaut syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.886
• PP5: Variant 2-166012254-C-T is Pathogenic according to our data. Variant chr2-166012254-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 68533.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS2: High AC in GnomAdExome4 at 6 AD,Unknown gene.

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN1A	NM_001165963.4	MANE Select	c.3734G>A	p.Arg1245Gln	missense	Exon 22 of 29	NP_001159435.1
	SCN1A	NM_001202435.3		c.3734G>A	p.Arg1245Gln	missense	Exon 21 of 28	NP_001189364.1
	SCN1A	NM_001353948.2		c.3734G>A	p.Arg1245Gln	missense	Exon 20 of 27	NP_001340877.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN1A	ENST00000674923.1	MANE Select	c.3734G>A	p.Arg1245Gln	missense	Exon 22 of 29	ENSP00000501589.1
	SCN1A	ENST00000303395.9	TSL:5	c.3734G>A	p.Arg1245Gln	missense	Exon 21 of 28	ENSP00000303540.4
	SCN1A	ENST00000375405.7	TSL:5	c.3701G>A	p.Arg1234Gln	missense	Exon 19 of 26	ENSP00000364554.3

Frequencies

GnomAD3 genomes AF: 0.00000662 AC: 1 AN: 151126 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.0000148

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000412 AC: 6 AN: 1457874 Hom.: 0 Cov.: 30 AF XY: 0.00000689 AC XY: 5 AN XY: 725290

African (AFR) AF: 0.00 AC: 0 AN: 33324

American (AMR) AF: 0.00 AC: 0 AN: 44440

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25974

East Asian (EAS) AF: 0.00 AC: 0 AN: 39532

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86116

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53318

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5738

European-Non Finnish (NFE) AF: 0.00000451 AC: 5 AN: 1109270

Other (OTH) AF: 0.00 AC: 0 AN: 60162

GnomAD4 genome AF: 0.00000662 AC: 1 AN: 151126 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 73814

African (AFR) AF: 0.00 AC: 0 AN: 41280

American (AMR) AF: 0.00 AC: 0 AN: 15116

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3448

East Asian (EAS) AF: 0.00 AC: 0 AN: 5164

South Asian (SAS) AF: 0.00 AC: 0 AN: 4818

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10596

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000148 AC: 1 AN: 67398

Other (OTH) AF: 0.00 AC: 0 AN: 2080

Alfa AF: 0.0000107 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Generalized epilepsy with febrile seizures plus, type 2 Pathogenic:2

Jan 29, 2021

New York Genome Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The inherited c.3734G>A (p.Arg1245Gln) variant identified in the SCN1A gene substitutes a very well conserved Arginine for Glutamine at amino acid 1245/2010(exon 22/29). This variant is found with low frequency in gnomAD(v3.0) (1 heterozygote, 0 homozygotes; allele frequency: 6.62e-6) suggesting it is not a common benign variant in the populations represented in that database. In silico algorithms predict this variant to be Damaging (SIFT; score:0.001) and Pathogenic (REVEL; score: 0.808) to the function of the canonical transcript. This variant is reported as Pathogenic / Likely Pathogenic in ClinVar (VarID: 68533). The c.3734G>A (p.Arg1245Gln) variant identified here has been previously reported in several individuals in the literature with SCN1A associated epilepsy syndromes [PMID:17054684; PMID: 21906962; PMID: 28202706]. Given its low frequency in population databases, observation in several affected individuals in the literature, and in silico predictions of pathogenicity, the inherited c.3734G>A (p.Arg1245Gln) variant identified in the SCN1A gene is reported as Likely Pathogenic.

Aug 19, 2022

MGZ Medical Genetics Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Pathogenic:2

Aug 29, 2023

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Jun 10, 2025

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Identified in multiple patients with Dravet syndrome or other SCN1A-related epilepsy referred for genetic testing at GeneDx and in published literature (PMID: 28202706, 21906962, 36993157); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This substitution is predicted to be within the extracellular loop between the S1 and S2 transmembrane segments of the third homologous domain; This variant is associated with the following publications: (PMID: 18804930, 21906962, 17054684, 24331359, 32347949, 24136861, 17381446, 31440721, 36993157, 35074891, 28202706)

Developmental and epileptic encephalopathy Pathogenic:1

Oct 28, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 1245 of the SCN1A protein (p.Arg1245Gln). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with autosomal dominant severe myoclonic epilepsy of infancy (PMID: 17054684, 21906962, 28202706). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 68533). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt SCN1A protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic.

Severe myoclonic epilepsy in infancy;C1858673:Generalized epilepsy with febrile seizures plus, type 2;C1864987:Migraine, familial hemiplegic, 3;C5543353:Developmental and epileptic encephalopathy 6B Pathogenic:1

Juno Genomics, Hangzhou Juno Genomics, Inc

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Multiple lines of computational evidence support a deleterious effect on the gene or gene product (conservation, evolutionary, splicing impact, etc).;Absent from controls (or at extremely low frequency if recessive) in Genome Aggregation Database, Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium.;Missense variant in a gene that has a low rate of benign missense variation and where missense variants are a common mechanism of disease.;The prevalence of the variant in affected individuals is significantly increased compared to the prevalence in controls.;Assumed de novo, but without confirmation of paternity and maternity.

Severe myoclonic epilepsy in infancy Other:1

UniProtKB/Swiss-Prot

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.97	D
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.0	M
PhyloP100		6.1
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-3.5	D
REVEL	Pathogenic	0.81
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.024	D
Polyphen		1.0	D
Vest4		0.84
MutPred		0.40		Gain of ubiquitination at K1246 (P = 0.1278)
MVP		1.0
MPC		1.1
ClinPred		0.99	D
GERP RS		5.7
Varity_R		0.61
gMVP		0.88
Mutation Taster		=0/100	disease causing (ClinVar)

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: rs121917912; hg19: chr2-166868764; COSMIC: COSV57689039; COSMIC: COSV57689039;