2-165139597-T-G

Variant names:

• chr2-165139597-T-G
• rs1946892
• NM_006922.4:c.2031A>C

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_006922.4(SCN3A):​c.2031A>C​(p.Thr677Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,552 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. T677T) has been classified as Benign. The gene SCN3A is included in the ClinGen Criteria Specification Registry.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SCN3A NM_006922.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.0720
• Publications: 0 publications found

Genes affected

SCN3A (HGNC:10590): (sodium voltage-gated channel alpha subunit 3) Voltage-gated sodium channels are transmembrane glycoprotein complexes composed of a large alpha subunit with 24 transmembrane domains and one or more regulatory beta subunits. They are responsible for the generation and propagation of action potentials in neurons and muscle. This gene encodes one member of the sodium channel alpha subunit gene family, and is found in a cluster of five alpha subunit genes on chromosome 2. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

SCN3A Gene-Disease associations (from GenCC):

• genetic developmental and epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Illumina, ClinGen, PanelApp Australia
• developmental and epileptic encephalopathy, 62

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• epilepsy, familial focal, with variable foci 4

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• undetermined early-onset epileptic encephalopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000236283 (HGNC:):

ACMG classification

Specifications for SCN3A are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.47).
• BP7: Synonymous conserved (PhyloP=-0.072 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006922.4. 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
	SCN3A	NM_006922.4	MANE Select	c.2031A>C	p.Thr677Thr	synonymous	Exon 14 of 28	NP_008853.3
	SCN3A	NM_001081676.2		c.1884A>C	p.Thr628Thr	synonymous	Exon 14 of 28	NP_001075145.1	Q9NY46-4
	SCN3A	NM_001081677.2		c.1884A>C	p.Thr628Thr	synonymous	Exon 14 of 28	NP_001075146.1	Q9NY46-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN3A	ENST00000283254.12	TSL:1 MANE Select	c.2031A>C	p.Thr677Thr	synonymous	Exon 14 of 28	ENSP00000283254.7	Q9NY46-3
	SCN3A	ENST00000409101.7	TSL:1	c.1884A>C	p.Thr628Thr	synonymous	Exon 14 of 28	ENSP00000386726.3	Q9NY46-2
	SCN3A	ENST00000706067.1		c.1980A>C	p.Thr660Thr	synonymous	Exon 14 of 28	ENSP00000516211.1	A0A994J5P2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461552 Hom.: 0 Cov.: 46 AF XY: 0.00 AC XY: 0 AN XY: 727076

African (AFR) AF: 0.00 AC: 0 AN: 33454

American (AMR) AF: 0.00 AC: 0 AN: 44698

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39682

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53394

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111806

Other (OTH) AF: 0.00 AC: 0 AN: 60372

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.47
CADD	Benign	16
DANN	Benign	0.73
PhyloP100		-0.072
Mutation Taster		=79/21	polymorphism

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: rs1946892; hg19: chr2-165996107;