2-165323345-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 3P and 4B. PP2PP3_ModerateBS2

The NM_001040142.2(SCN2A):c.1861C>T(p.Arg621Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000041 in 1,461,878 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R621S) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

SCN2A
NM_001040142.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 4.91

Publications

0 publications found

Variant links:

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]

SCN2A Gene-Disease associations (from GenCC):

complex neurodevelopmental disorder
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen, Illumina
developmental and epileptic encephalopathy, 11
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
intellectual disability
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
episodic ataxia, type 9
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
seizures, benign familial infantile, 3
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
benign familial infantile epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
benign familial neonatal-infantile seizures
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Dravet syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
genetic developmental and epileptic encephalopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
infantile spasms
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
malignant migrating partial seizures of infancy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

SCN2A links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

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 genetic developmental and epileptic encephalopathy, episodic ataxia, type 9, seizures, benign familial infantile, 3, complex neurodevelopmental disorder, benign familial neonatal-infantile seizures, Dravet syndrome, infantile spasms, developmental and epileptic encephalopathy, 11, intellectual disability, benign familial infantile epilepsy, malignant migrating partial seizures of infancy.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.853

BS2

High AC in GnomAdExome4 at 6 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN2A	NM_001040142.2 link	c.1861C>T	p.Arg621Cys	missense_variant	Exon 12 of 27	ENST00000375437.7	NP_001035232.1
SCN2A	NM_001371246.1 link	c.1861C>T	p.Arg621Cys	missense_variant	Exon 12 of 27	ENST00000631182.3	NP_001358175.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein
SCN2A	ENST00000375437.7 link	c.1861C>T	p.Arg621Cys	missense_variant	Exon 12 of 27	5	NM_001040142.2	ENSP00000364586.2
SCN2A	ENST00000631182.3 link	c.1861C>T	p.Arg621Cys	missense_variant	Exon 12 of 27	5	NM_001371246.1	ENSP00000486885.1
SCN2A	ENST00000283256.10 link	c.1861C>T	p.Arg621Cys	missense_variant	Exon 12 of 27	1		ENSP00000283256.6

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

250956

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000410

AC:

AN:

1461878

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727240

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000450

AC:

AN:

1112004

Other (OTH)

AF:

0.00

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

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

Uncertain:2

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Oct 18, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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. 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. ClinVar contains an entry for this variant (Variation ID: 207092). This missense change has been observed in individual(s) with Lennox-Gastaut syndrome (Invitae). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 621 of the SCN2A protein (p.Arg621Cys). -

Inborn genetic diseases

Uncertain:1

Mar 27, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.1861C>T (p.R621C) alteration is located in exon 12 (coding exon 11) of the SCN2A gene. This alteration results from a C to T substitution at nucleotide position 1861, causing the arginine (R) at amino acid position 621 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Aug 23, 2013

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The R621C variant 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. The R621C variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution alters a highly conserved position in the cytoplasmic loop between the first and second homologous domains of the SCN2A protein (Shi et al., 2012), and in silico analysis predicts this variant is probably damaging to the protein structure/function. The variant is found in SCN2A panel(s). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.24

BayesDel_addAF

Pathogenic

0.49

BayesDel_noAF

Pathogenic

0.46

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.85

D;.;T;.;D;D;.

Eigen

Pathogenic

0.88

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Uncertain

0.95

D;.;D;.;.;.;D

M_CAP

Pathogenic

0.34

MetaRNN

Pathogenic

0.85

D;D;D;D;D;D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.3

M;M;.;M;M;M;M

PhyloP100

4.9

PrimateAI

Uncertain

0.63

PROVEAN

Pathogenic

-6.3

D;.;.;.;.;D;D

REVEL

Pathogenic

0.77

Sift

Pathogenic

0.0

D;.;.;.;.;D;D

Sift4G

Uncertain

0.0020

D;.;.;D;.;D;D

Polyphen

1.0

D;D;.;D;D;D;D

Vest4

0.79

MutPred

0.37

Loss of solvent accessibility (P = 0.0036);Loss of solvent accessibility (P = 0.0036);.;Loss of solvent accessibility (P = 0.0036);Loss of solvent accessibility (P = 0.0036);Loss of solvent accessibility (P = 0.0036);Loss of solvent accessibility (P = 0.0036);

MVP

0.97

ClinPred

1.0

GERP RS

5.6

Varity_R

0.60

gMVP

0.71

Mutation Taster

=14/86

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over