2-166012236-A-G

Variant names:

• chr2-166012236-A-G
• rs749638533
• NM_001165963.4:c.3752T>C

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 5P and 5B. PM1 PM5 PP2 BP6 BS2

The NM_001165963.4(SCN1A):​c.3752T>C​(p.Met1251Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000621 in 1,609,902 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M1251R) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000033 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: SCN1A NM_001165963.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 9.32
• Publications: 1 publications found

Genes affected

SCN1A (HGNC:10585): (sodium voltage-gated channel alpha subunit 1) Voltage-dependent sodium channels are heteromeric complexes that regulate sodium exchange between intracellular and extracellular spaces and are essential for the generation and propagation of action potentials in muscle cells and neurons. Each sodium channel is composed of a large pore-forming, glycosylated alpha subunit and two smaller beta subunits. This gene encodes a sodium channel alpha subunit, which has four homologous domains, each of which contains six transmembrane regions. Allelic variants of this gene are associated with generalized epilepsy with febrile seizures and epileptic encephalopathy. Alternative splicing results in multiple transcript variants. The RefSeq Project has decided to create four representative RefSeq records. Three of the transcript variants are supported by experimental evidence and the fourth contains alternate 5' untranslated exons, the exact combination of which have not been experimentally confirmed for the full-length transcript. [provided by RefSeq, Oct 2015]

SCN1A-AS1 (HGNC:54069): (SCN1A and SCN9A antisense RNA 1)

LOC102724058 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 9 uncertain in NM_001165963.4
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-166012236-A-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 580762.
• PP2: Missense variant in the SCN1A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 848 curated pathogenic missense variants (we use a threshold of 10). The gene has 89 curated benign missense variants. Gene score misZ: 5.2206 (above the threshold of 3.09). Trascript score misZ: 7.6022 (above the threshold of 3.09). GenCC associations: The gene is linked to familial or sporadic hemiplegic migraine, myoclonic-astatic epilepsy, arthrogryposis, Dravet syndrome, malignant migrating partial seizures of infancy, generalized epilepsy with febrile seizures plus, type 2, migraine, familial hemiplegic, 3, developmental and epileptic encephalopathy, 6A, familial hemiplegic migraine, generalized epilepsy with febrile seizures plus, genetic developmental and epileptic encephalopathy, Lennox-Gastaut syndrome.
• BP6: Variant 2-166012236-A-G is Benign according to our data. Variant chr2-166012236-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 408940.
• BS2: High AC in GnomAd4 at 5 AD,Unknown gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001165963.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN1A	NM_001165963.4	MANE Select	c.3752T>C	p.Met1251Thr	missense	Exon 22 of 29	NP_001159435.1
	SCN1A	NM_001202435.3		c.3752T>C	p.Met1251Thr	missense	Exon 21 of 28	NP_001189364.1
	SCN1A	NM_001353948.2		c.3752T>C	p.Met1251Thr	missense	Exon 20 of 27	NP_001340877.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN1A	ENST00000674923.1	MANE Select	c.3752T>C	p.Met1251Thr	missense	Exon 22 of 29	ENSP00000501589.1
	SCN1A	ENST00000303395.9	TSL:5	c.3752T>C	p.Met1251Thr	missense	Exon 21 of 28	ENSP00000303540.4
	SCN1A	ENST00000375405.7	TSL:5	c.3719T>C	p.Met1240Thr	missense	Exon 19 of 26	ENSP00000364554.3

Frequencies

GnomAD3 genomes AF: 0.0000264 AC: 4 AN: 151286 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000725

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000194

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000201 AC: 5 AN: 249350 AF XY: 0.0000148

Gnomad AFR exome AF: 0.000186

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000178

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000343 AC: 5 AN: 1458498 Hom.: 0 Cov.: 30 AF XY: 0.00000276 AC XY: 2 AN XY: 725554

African (AFR) AF: 0.0000600 AC: 2 AN: 33338

American (AMR) AF: 0.00 AC: 0 AN: 44480

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25982

East Asian (EAS) AF: 0.00 AC: 0 AN: 39544

South Asian (SAS) AF: 0.00 AC: 0 AN: 86154

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53322

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5738

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1109746

Other (OTH) AF: 0.00 AC: 0 AN: 60194

GnomAD4 genome AF: 0.0000330 AC: 5 AN: 151404 Hom.: 0 Cov.: 32 AF XY: 0.0000270 AC XY: 2 AN XY: 73998

African (AFR) AF: 0.0000964 AC: 4 AN: 41482

American (AMR) AF: 0.00 AC: 0 AN: 15150

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3444

East Asian (EAS) AF: 0.000194 AC: 1 AN: 5154

South Asian (SAS) AF: 0.00 AC: 0 AN: 4822

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10616

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67422

Other (OTH) AF: 0.00 AC: 0 AN: 2110

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000189

ExAC AF: 0.0000330 AC: 4

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	2	-	not provided (2)
-	-	1	Developmental and epileptic encephalopathy (1)
-	1	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.33
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Pathogenic	0.23
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.95	D
Eigen	Uncertain	0.34
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.89	D
M_CAP	Pathogenic	0.45	D
MetaRNN	Uncertain	0.74	D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Benign	0.79	N
PhyloP100		9.3
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-3.3	D
REVEL	Pathogenic	0.80
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.036	D
Polyphen		0.79	P
Vest4		0.83
MutPred		0.60		Loss of stability (P = 0.0792)
MVP		0.90
MPC		0.99
ClinPred		0.75	D
GERP RS		5.5
Varity_R		0.65
gMVP		0.95
Mutation Taster		=3/97	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.10		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: rs749638533; hg19: chr2-166868746;