rs121917914

Positions:

• chr2-165992387-C-G
• chr2-165992387-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PS1_Moderate PM1 PM2 PP2 PP3 PP5_Moderate

The NM_001165963.4(SCN1A):​c.4888G>C​(p.Val1630Leu) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,566 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 Pathogenic (★). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin UniProt.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SCN1A NM_001165963.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 4.80

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 10 ACMG points.

• PS1: Transcript NM_001165963.4 (SCN1A) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in UniProt
• PM1: In a repeat IV (size 298) in uniprot entity SCN1A_HUMAN there are 62 pathogenic changes around while only 3 benign (95%) in NM_001165963.4
• 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, 0.761
• PP5: Variant 2-165992387-C-G is Pathogenic according to our data. Variant chr2-165992387-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 2203174.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SCN1A	NM_001165963.4	c.4888G>C	p.Val1630Leu	missense_variant	29/29	ENST00000674923.1	NP_001159435.1
LOC102724058	NR_110598.1	n.176-23226C>G		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SCN1A	ENST00000674923.1	c.4888G>C	p.Val1630Leu	missense_variant	29/29		NM_001165963.4	ENSP00000501589	P4
SCN1A-AS1	ENST00000651574.1	n.193-23226C>G		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461566 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727104

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 17, 2022

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. For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Val1630 amino acid residue in SCN1A. Other variant(s) that disrupt this residue have been observed in individuals with SCN1A-related conditions (PMID: 17561957, 27465585), which suggests that this may be a clinically significant amino acid residue. This missense change has been observed in individual(s) with borderline severe myoclonic epilepsy in infancy (PMID: 23195492). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 1630 of the SCN1A protein (p.Val1630Leu). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	.;.;.;D;.;D;.;.;.
Eigen	Uncertain	0.23
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.89	D;D;D;D;.;.;.;D;D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.76	D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.85	D
MutationAssessor	Benign	1.6	.;.;.;L;.;L;.;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.87	D
PROVEAN	Benign	-2.0	.;.;.;N;.;N;.;N;N
REVEL	Pathogenic	0.70
Sift	Benign	0.034	.;.;.;D;.;D;.;D;D
Sift4G	Benign	0.14	.;.;.;T;.;T;.;T;T
Polyphen		0.25	.;.;.;.;B;.;B;B;.
Vest4		0.59, 0.54, 0.52, 0.74
MutPred		0.64		.;.;.;Gain of catalytic residue at V1630 (P = 0.0836);.;Gain of catalytic residue at V1630 (P = 0.0836);.;.;.;
MVP		0.99
MPC		1.7
ClinPred		0.97	D
GERP RS		5.3
Varity_R		0.31
gMVP		0.96

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: rs121917914; hg19: chr2-166848897;