2-165992171-C-A

Position:

• chr2-165992171-C-A

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Moderate PP5_Moderate

The NM_001165963.4(SCN1A):​c.5104G>T​(p.Asp1702Tyr) 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: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 4.06

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 Likely_pathogenic. Variant got 9 ACMG points.

• 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, 0.926
• PP5: Variant 2-165992171-C-A is Pathogenic according to our data. Variant chr2-165992171-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 206857.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.5104G>T	p.Asp1702Tyr	missense_variant	29/29	ENST00000674923.1	NP_001159435.1
LOC102724058	NR_110598.1	n.176-23442C>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SCN1A	ENST00000674923.1	c.5104G>T	p.Asp1702Tyr	missense_variant	29/29		NM_001165963.4	ENSP00000501589	P4
SCN1A-AS1	ENST00000651574.1	n.193-23442C>A		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Apr 19, 2018

p.Asp1702Tyr (GAT>TAT): c.5104 G>T in exon 26 of the SCN1A gene (NM_001165963.1) The Asp1702Tyr missense change has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. It was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Asp1702Tyr is a non-conservative amino acid substitution as a negatively charged Aspartic acid residue is replaced with an uncharged Tyrosine residue, and it alters a highly conserved position in the pore loop between the S5 and S6 segments of the fourth transmembrane domain. Multiple in silico algorithms predict that Asp1720Tyr is possibly damaging to the structure/function of the SCN1A protein.Therefore, based on the currently available information, Asp1720Tyr is a strong candidate for a disease-causing mutation, although the possibility that it is a benign variant cannot be excluded. The variant is found in INFANT-EPI panel(s). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	.;.;.;D;.;D;.;.;.
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.97	D;D;D;D;.;.;.;D;D
M_CAP	Pathogenic	0.90	D
MetaRNN	Pathogenic	0.93	D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.4	.;.;.;H;.;H;.;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.77	T
PROVEAN	Pathogenic	-7.6	.;.;.;D;.;D;.;D;D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	.;.;.;D;.;D;.;D;D
Sift4G	Pathogenic	0.0	.;.;.;D;.;D;.;D;D
Polyphen		1.0	.;.;.;.;D;.;D;D;.
Vest4		0.67, 0.77, 0.77, 0.89
MutPred		0.61		.;.;.;Gain of loop (P = 0.0851);.;Gain of loop (P = 0.0851);.;.;.;
MVP		0.99
MPC		2.0
ClinPred		1.0	D
GERP RS		4.6
Varity_R		0.91
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

LitVar

Other links and lift over

dbSNP: rs748333147; hg19: chr2-166848681;