NM_001040142.2:c.5752C>A

Variant names:

• chr2-165389558-C-A
• rs139899756
• NM_001040142.2:c.5752C>A

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_001040142.2(SCN2A):​c.5752C>A​(p.Arg1918Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,706 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign 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. R1918H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SCN2A NM_001040142.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.04
• Publications: 0 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.27705908).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN2A	NM_001040142.2	c.5752C>A	p.Arg1918Ser	missense_variant	Exon 27 of 27	ENST00000375437.7	NP_001035232.1
SCN2A	NM_001371246.1	c.5752C>A	p.Arg1918Ser	missense_variant	Exon 27 of 27	ENST00000631182.3	NP_001358175.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN2A	ENST00000375437.7	c.5752C>A	p.Arg1918Ser	missense_variant	Exon 27 of 27	5	NM_001040142.2	ENSP00000364586.2
SCN2A	ENST00000631182.3	c.5752C>A	p.Arg1918Ser	missense_variant	Exon 27 of 27	5	NM_001371246.1	ENSP00000486885.1
SCN2A	ENST00000283256.10	c.5752C>A	p.Arg1918Ser	missense_variant	Exon 27 of 27	1		ENSP00000283256.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461706 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 727150

African (AFR) AF: 0.00 AC: 0 AN: 33464

American (AMR) AF: 0.00 AC: 0 AN: 44694

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53396

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111936

Other (OTH) AF: 0.0000166 AC: 1 AN: 60386

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Sep 24, 2019

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed in large population cohorts (Lek et al., 2016); The majority of missense variants in this gene are considered pathogenic (Stenson et al., 2014); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This substitution is predicted to be within the C-terminal cytoplasmic domain -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.060
CADD	Benign	23
DANN	Benign	0.93
DEOGEN2	Uncertain	0.70	D;.;T;.;D;D;.
Eigen	Benign	-0.15
Eigen_PC	Benign	0.032
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.83	T;.;T;.;.;.;T
M_CAP	Benign	0.048	D
MetaRNN	Benign	0.28	T;T;T;T;T;T;T
MetaSVM	Uncertain	0.25	D
MutationAssessor	Benign	1.2	L;L;.;L;L;L;L
PhyloP100		2.0
PrimateAI	Benign	0.38	T
PROVEAN	Benign	-2.0	N;.;.;.;.;N;N
REVEL	Uncertain	0.39
Sift	Benign	0.18	T;.;.;.;.;T;T
Sift4G	Benign	0.49	T;.;.;T;.;T;T
Polyphen		0.0	B;B;.;B;B;B;B
Vest4		0.18
MutPred		0.42		Loss of stability (P = 0.0543);Loss of stability (P = 0.0543);.;Loss of stability (P = 0.0543);Loss of stability (P = 0.0543);Loss of stability (P = 0.0543);Loss of stability (P = 0.0543);
MVP		0.76
ClinPred		0.51	D
GERP RS		5.0
Varity_R		0.55
gMVP		0.91
Mutation Taster		=29/71	disease causing

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

Other links and lift over

dbSNP: rs139899756; hg19: chr2-166246068;