rs867268264

Variant names:

• chr2-165331357-C-T
• rs867268264
• NM_001040142.2:c.2177C>T

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 5P and 5B. PM1 PP2 PP3_Moderate BS1_Supporting BS2

The NM_001040142.2(SCN2A):​c.2177C>T​(p.Pro726Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000958 in 1,461,408 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 (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000096 (0 hom.)
• Consequence: SCN2A NM_001040142.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 7.91
• Publications: 3 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 0 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 uncertain in NM_001040142.2
• 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, 0.888
• BS1: Variant frequency is greater than expected in population mid. GnomAdExome4 allele frequency = 0.00000958 (14/1461408) while in subpopulation MID AF = 0.00225 (13/5766). AF 95% confidence interval is 0.00133. There are 0 homozygotes in GnomAdExome4. There are 6 alleles in the male GnomAdExome4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAdExome4 at 14 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN2A	NM_001040142.2	c.2177C>T	p.Pro726Leu	missense_variant	Exon 14 of 27	ENST00000375437.7	NP_001035232.1
SCN2A	NM_001371246.1	c.2177C>T	p.Pro726Leu	missense_variant	Exon 14 of 27	ENST00000631182.3	NP_001358175.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN2A	ENST00000375437.7	c.2177C>T	p.Pro726Leu	missense_variant	Exon 14 of 27	5	NM_001040142.2	ENSP00000364586.2
SCN2A	ENST00000631182.3	c.2177C>T	p.Pro726Leu	missense_variant	Exon 14 of 27	5	NM_001371246.1	ENSP00000486885.1
SCN2A	ENST00000283256.10	c.2177C>T	p.Pro726Leu	missense_variant	Exon 14 of 27	1		ENSP00000283256.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000958 AC: 14 AN: 1461408 Hom.: 0 Cov.: 32 AF XY: 0.00000825 AC XY: 6 AN XY: 726984

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

American (AMR) AF: 0.00 AC: 0 AN: 44668

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26118

East Asian (EAS) AF: 0.00 AC: 0 AN: 39686

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00225 AC: 13 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111676

Other (OTH) AF: 0.0000166 AC: 1 AN: 60370

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Apr 15, 2019

Mayo Clinic Laboratories, Mayo Clinic

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 17, 2022

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Oct 05, 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: 533487). This variant has not been reported in the literature in individuals affected with SCN2A-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 726 of the SCN2A protein (p.Pro726Leu). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.57
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.87	D;.;T;.;D;D;.
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D;.;D;.;.;.;D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.89	D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Uncertain	2.3	M;M;.;M;M;M;M
PhyloP100		7.9
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-9.0	D;.;.;.;.;D;D
REVEL	Pathogenic	0.80
Sift	Pathogenic	0.0	D;.;.;.;.;D;D
Sift4G	Benign	0.42	T;.;.;T;.;T;T
Polyphen		1.0	D;D;.;D;D;D;D
Vest4		0.62
MutPred		0.42		Loss of glycosylation at P726 (P = 0.0188);Loss of glycosylation at P726 (P = 0.0188);.;Loss of glycosylation at P726 (P = 0.0188);Loss of glycosylation at P726 (P = 0.0188);Loss of glycosylation at P726 (P = 0.0188);Loss of glycosylation at P726 (P = 0.0188);
MVP		0.92
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.83
gMVP		0.96

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: rs867268264; hg19: chr2-166187867;