rs121917752

Positions:

• chr2-165309414-G-A

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_001040142.2(SCN2A):​c.668G>A​(p.Arg223Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,460 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 11/18 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SCN2A NM_001040142.2 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5 O:1
• Conservation: PhyloP100: 10.0

Genes affected

SCN2A (HGNC:10588): (sodium voltage-gated channel alpha subunit 2) Voltage-gated sodium channels are transmembrane glycoprotein complexes composed of a large alpha subunit with four repeat domains, each of which is composed of six membrane-spanning segments, and one or more regulatory beta subunits. Voltage-gated sodium channels function in the generation and propagation of action potentials in neurons and muscle. This gene encodes one member of the sodium channel alpha subunit gene family. Allelic variants of this gene are associated with seizure disorders and autism spectrum disorder. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2016]

ACMG classification

Verdict is Pathogenic. Variant got 17 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_001040142.2
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SCN2A. . Trascript score misZ 8.7114 (greater than threshold 3.09). GenCC has associacion of gene with seizures, benign familial infantile, 3, Dravet syndrome, benign familial neonatal-infantile seizures, malignant migrating partial seizures of infancy, complex neurodevelopmental disorder, developmental and epileptic encephalopathy, 11, developmental and epileptic encephalopathy, West syndrome, benign familial infantile epilepsy, episodic ataxia, type 9.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 2-165309414-G-A is Pathogenic according to our data. Variant chr2-165309414-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 12879.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SCN2A	NM_001040142.2	c.668G>A	p.Arg223Gln	missense_variant	6/27	ENST00000375437.7
SCN2A	NM_001371246.1	c.697+158G>A		intron_variant		ENST00000631182.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SCN2A	ENST00000375437.7	c.668G>A	p.Arg223Gln	missense_variant	6/27	5	NM_001040142.2	P1
SCN2A	ENST00000631182.3	c.697+158G>A		intron_variant		5	NM_001371246.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461460 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727034

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000383

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Developmental and epileptic encephalopathy, 11 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Institute of Human Genetics, University of Leipzig Medical Center

Aug 16, 2019

- -

Seizures, benign familial infantile, 3;C3150987:Developmental and epileptic encephalopathy, 11 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 11, 2023

ClinVar contains an entry for this variant (Variation ID: 12879). 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 SCN2A protein function. Experimental studies have shown that this missense change affects SCN2A function (PMID: 17021166). For these reasons, this variant has been classified as Pathogenic. This missense change has been observed in individuals with benign familial neonatal-infantile seizures (PMID: 15048894, 23360469, 29215089). It has also been observed to segregate with disease in related individuals. This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 223 of the SCN2A protein (p.Arg223Gln). This variant is not present in population databases (gnomAD no frequency). -

Benign familial infantile epilepsy Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Neurology Department, Shenzhen Children's Hospital

Feb 16, 2022

- -

Seizures, benign familial infantile, 3 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Apr 01, 2004

- -

Seizure Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

Diagnostic Laboratory, Strasbourg University Hospital

-

- -

Complex neurodevelopmental disorder Other:1

not provided, no classification provided

literature only

Channelopathy-Associated Epilepsy Research Center

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	31
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.99	.;D;T;D;D;D
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	1.0	D;D;D;.;.;D
M_CAP	Pathogenic	0.86	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Pathogenic	4.8	.;H;.;H;H;.
MutationTaster	Benign	1.0	A;A;A;A
PROVEAN	Uncertain	-4.0	D;D;.;.;D;.
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;D;.;.;D;.
Sift4G	Pathogenic	0.0	D;D;.;.;D;D
Polyphen		1.0	.;D;.;D;D;.
Vest4		0.99
MutPred		0.96		Loss of MoRF binding (P = 0.0209);Loss of MoRF binding (P = 0.0209);.;Loss of MoRF binding (P = 0.0209);Loss of MoRF binding (P = 0.0209);.;
MVP		0.99
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.92

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: rs121917752; hg19: chr2-166165924;