NM_001099404.2:c.959C>A

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001099404.2(SCN5A):c.959C>A(p.Thr320Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,459,582 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. T320I) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

SCN5A
NM_001099404.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2O:1

Conservation

PhyloP100: 2.06

Publications

7 publications found

Variant links:

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

SCN5A links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN5A	NM_001099404.2 link	c.959C>A	p.Thr320Asn	missense_variant	Exon 8 of 28	ENST00000413689.6	NP_001092874.1	Q14524H9KVD2
SCN5A	NM_000335.5 link	c.959C>A	p.Thr320Asn	missense_variant	Exon 8 of 28	ENST00000423572.7	NP_000326.2	Q14524-2Q86V90

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN5A	ENST00000413689.6 link	c.959C>A	p.Thr320Asn	missense_variant	Exon 8 of 28	5	NM_001099404.2	ENSP00000410257.1		H9KVD2
SCN5A	ENST00000423572.7 link	c.959C>A	p.Thr320Asn	missense_variant	Exon 8 of 28	1	NM_000335.5	ENSP00000398266.2		Q14524-2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000802

AC:

AN:

249254

AF XY:

0.0000148

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.000199

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000206

AC:

AN:

1459582

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

726260

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33424

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.000115

AC:

AN:

26120

East Asian (EAS)

AF:

0.00

AC:

AN:

39688

South Asian (SAS)

AF:

0.00

AC:

AN:

86220

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53348

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1109998

Other (OTH)

AF:

0.00

AC:

AN:

60300

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000439

Hom.:

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Sep 08, 2022

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Identified in a patient with suspected Brugada syndrome in the published literature (Kapplinger et al., 2010); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 20129283, 30662450) -

Jan 06, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces threonine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 320 of the SCN5A protein (p.Thr320Asn). This variant is present in population databases (rs199473091, gnomAD 0.03%). This missense change has been observed in individual(s) with Brugada syndrome or long-QT syndrome (PMID: 19841300, 25904541). ClinVar contains an entry for this variant (Variation ID: 68061). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant¬†is likely to be tolerated. 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. -

Brugada syndrome

Other:1

Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

This variant has been reported as associated with Brugada syndrome in the following publications (PMID:20129283). This is a literature report, and does not necessarily reflect the clinical interpretation of the Imperial College / Royal Brompton Cardiovascular Genetics laboratory. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.50

CardioboostArm

Benign

0.000034

CardioboostCm

Benign

0.011

BayesDel_addAF

Uncertain

0.15

BayesDel_noAF

Uncertain

-0.020

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.80

.;.;.;.;.;D;.;.;.

Eigen

Uncertain

0.21

Eigen_PC

Uncertain

0.27

FATHMM_MKL

Uncertain

0.76

LIST_S2

Uncertain

0.86

.;D;D;D;D;D;D;.;D

M_CAP

Pathogenic

0.41

MetaRNN

Uncertain

0.66

D;D;D;D;D;D;D;D;D

MetaSVM

Pathogenic

0.87

MutationAssessor

Benign

1.8

.;L;.;.;.;L;.;.;.

PhyloP100

2.1

PrimateAI

Uncertain

0.62

PROVEAN

Uncertain

-2.4

N;N;N;N;N;N;N;N;N

REVEL

Uncertain

0.44

Sift

Benign

0.036

D;D;D;D;T;D;D;T;T

Sift4G

Benign

0.35

T;T;T;T;T;T;T;T;T

Polyphen

0.077

B;P;.;B;.;D;D;.;.

Vest4

0.40

MutPred

0.82

Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);

MVP

0.88

MPC

1.2

ClinPred

0.68

GERP RS

5.3

Varity_R

0.19

gMVP

0.90

Mutation Taster

=0/100

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

Splicevardb

2.0

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over