2-165314005-C-T

Variant names:

• chr2-165314005-C-T
• NM_001040142.2:c.1280C>T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP2 PP3

The NM_001040142.2(SCN2A):​c.1280C>T​(p.Ala427Val) 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A427D) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SCN2A NM_001040142.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.91

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 Likely_pathogenic. Variant got 8 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, 6 uncertain in NM_001040142.2
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-165314005-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 130212.We mark this variant Likely_pathogenic, oryginal submissions are: {not_provided=1, Uncertain_significance=1, Pathogenic=1}.
• PP2: Missense variant in the SCN2A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 362 curated pathogenic missense variants (we use a threshold of 10). The gene has 36 curated benign missense variants. Trascript score misZ: 8.7114 (above the threshold of 3.09). GenCC associations: The gene is linked to 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, 0.811

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN2A	NM_001040142.2	c.1280C>T	p.Ala427Val	missense_variant	Exon 10 of 27	ENST00000375437.7	NP_001035232.1
SCN2A	NM_001371246.1	c.1280C>T	p.Ala427Val	missense_variant	Exon 10 of 27	ENST00000631182.3	NP_001358175.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN2A	ENST00000375437.7	c.1280C>T	p.Ala427Val	missense_variant	Exon 10 of 27	5	NM_001040142.2	ENSP00000364586.2
SCN2A	ENST00000631182.3	c.1280C>T	p.Ala427Val	missense_variant	Exon 10 of 27	5	NM_001371246.1	ENSP00000486885.1
SCN2A	ENST00000283256.10	c.1280C>T	p.Ala427Val	missense_variant	Exon 10 of 27	1		ENSP00000283256.6
SCN2A	ENST00000424833.5	c.1280C>T	p.Ala427Val	missense_variant	Exon 10 of 11	1		ENSP00000406454.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Oct 18, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 427 of the SCN2A protein (p.Ala427Val). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SCN2A-related conditions. 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. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	27
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.96	.;D;.;T;.;D;D;.
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D;D;.;D;.;.;.;D
M_CAP	Pathogenic	0.60	D
MetaRNN	Pathogenic	0.81	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	.;M;M;.;M;M;M;M
PrimateAI	Pathogenic	0.90	D
PROVEAN	Uncertain	-3.8	D;D;.;.;.;.;D;D
REVEL	Pathogenic	0.78
Sift	Pathogenic	0.0	D;D;.;.;.;.;D;D
Sift4G	Pathogenic	0.0010	D;D;.;.;D;.;D;D
Polyphen		1.0, 1.0	.;D;D;.;D;D;D;D
Vest4		0.73, 0.72, 0.73, 0.73
MutPred		0.40		Loss of disorder (P = 0.0883);Loss of disorder (P = 0.0883);Loss of disorder (P = 0.0883);.;Loss of disorder (P = 0.0883);Loss of disorder (P = 0.0883);Loss of disorder (P = 0.0883);Loss of disorder (P = 0.0883);
MVP		0.97
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.86
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: chr2-166170515; COSMIC: COSV105105080; COSMIC: COSV105105080;