NM_001099404.2:c.2821_2822delTCinsAT

Variant names:

• chr3-38581337-GA-AT
• rs137854605
• NM_001099404.2:c.2821_2822delTCinsAT

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM5 PP3

The NM_001099404.2(SCN5A):​c.2821_2822delTCinsAT​(p.Ser941Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. 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. S941N) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SCN5A NM_001099404.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 10.0
• Publications: 0 publications found

Genes affected

SCN5A (HGNC:10593): (sodium voltage-gated channel alpha subunit 5) The protein encoded by this gene is an integral membrane protein and tetrodotoxin-resistant voltage-gated sodium channel subunit. This protein is found primarily in cardiac muscle and is responsible for the initial upstroke of the action potential in an electrocardiogram. Defects in this gene have been associated with long QT syndrome type 3 (LQT3), atrial fibrillation, cardiomyopathy, and Brugada syndrome 1, all autosomal dominant cardiac diseases. Alternative splicing results in several transcript variants encoding different isoforms. [provided by RefSeq, May 2022]

SCN5A Gene-Disease associations (from GenCC):

• Brugada syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Brugada syndrome 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Laboratory for Molecular Medicine, G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• dilated cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• dilated cardiomyopathy 1E

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• familial long QT syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• long QT syndrome 3

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P
• sick sinus syndrome 1

  Inheritance: AD, AR Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
• progressive familial heart block, type 1A

  Inheritance: SD, AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Genomics England PanelApp
• atrial standstill

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial atrial fibrillation

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial sick sinus syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• paroxysmal familial ventricular fibrillation

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• progressive familial heart block

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• catecholaminergic polymorphic ventricular tachycardia

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
• short QT syndrome

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-38581337-GA-TT is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 9384.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN5A	NM_001099404.2	c.2821_2822delTCinsAT	p.Ser941Ile	missense_variant		ENST00000413689.6	NP_001092874.1
SCN5A	NM_000335.5	c.2821_2822delTCinsAT	p.Ser941Ile	missense_variant		ENST00000423572.7	NP_000326.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN5A	ENST00000413689.6	c.2821_2822delTCinsAT	p.Ser941Ile	missense_variant		5	NM_001099404.2	ENSP00000410257.1
SCN5A	ENST00000423572.7	c.2821_2822delTCinsAT	p.Ser941Ile	missense_variant		1	NM_000335.5	ENSP00000398266.2

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jan 17, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant disrupts the p.Ser941 amino acid residue in SCN5A. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 17698727, 10911008). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. This sequence change replaces serine with isoleucine at codon 941 of the SCN5A protein (p.Ser941Ile). The serine residue is highly conserved and there is a large physicochemical difference between serine and isoleucine. The frequency data for this variant in the population databases is not available, as this variant may be reported as separate entries in the ExAC database. This variant has not been reported in the literature in individuals with SCN5A-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Not Available"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Not Available"). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		10

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs137854605; hg19: chr3-38622828;