3-38598948-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2PP2BP4

The NM_000335.5(SCN5A):c.1993G>A(p.Ala665Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0000322 in 1,613,748 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000031 ( 0 hom. )

Consequence

SCN5A
NM_000335.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7B:1

Conservation

PhyloP100: 4.11

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the SCN5A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 99 curated pathogenic missense variants (we use a threshold of 10). The gene has 60 curated benign missense variants. Gene score misZ: 2.7504 (below the threshold of 3.09). Trascript score misZ: 4.8279 (above the threshold of 3.09). GenCC associations: The gene is linked to progressive familial heart block, type 1A, Brugada syndrome, familial sick sinus syndrome, short QT syndrome, paroxysmal familial ventricular fibrillation, progressive familial heart block, long QT syndrome 3, familial atrial fibrillation, catecholaminergic polymorphic ventricular tachycardia, dilated cardiomyopathy, dilated cardiomyopathy 1E, arrhythmogenic right ventricular cardiomyopathy, Brugada syndrome 1, atrial standstill, familial isolated dilated cardiomyopathy, familial long QT syndrome, sick sinus syndrome 1.

BP4

Computational evidence support a benign effect (MetaRNN=0.30315655).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN5A	NM_001099404.2 link	c.1993G>A	p.Ala665Thr	missense_variant	Exon 13 of 28	ENST00000413689.6	NP_001092874.1	Q14524H9KVD2
SCN5A	NM_000335.5 link	c.1993G>A	p.Ala665Thr	missense_variant	Exon 13 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.1993G>A	p.Ala665Thr	missense_variant	Exon 13 of 28	5	NM_001099404.2	ENSP00000410257.1		H9KVD2
SCN5A	ENST00000423572.7 link	c.1993G>A	p.Ala665Thr	missense_variant	Exon 13 of 28	1	NM_000335.5	ENSP00000398266.2		Q14524-2

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152178

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000385

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000643

AC:

AN:

249002

Hom.:

AF XY:

0.0000667

AC XY:

AN XY:

135014

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000278

Gnomad SAS exome

AF:

0.000359

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000315

AC:

AN:

1461570

Hom.:

Cov.:

AF XY:

0.0000344

AC XY:

AN XY:

727070

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000504

Gnomad4 SAS exome

AF:

0.000394

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000540

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152178

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74338

show subpopulations

Gnomad4 AFR

AF:

0.0000724

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000385

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.00000543

Hom.:

Bravo

AF:

0.0000302

ExAC

AF:

0.0000412

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Aug 23, 2018

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

A variant of uncertain significance has been identified in the SCN5A gene. The A665T variant has not been published as pathogenic or been reported as benign to our knowledge. The A665T variant is observed in 18/276636 (0.0065%) alleles from individuals of multiple ethnic backgrounds in large population cohorts (Lek et al., 2016). In-silico analyses, including protein predictors and evolutionary conservation, support that this variant does not alter protein structure/function. Nevertheless, the A665T variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. Finally, although another missense variant at this same residue (A665S) has been reported in the Human Gene Mutation Database in association with LQTS (Stenson et al., 2014), the pathogenicity of this variant has not been definitively determined. Therefore, based on the currently available information, it is unclear whether this variant is pathogenic or rare benign. -

Jan 15, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 665 of the SCN5A protein (p.Ala665Thr). This variant is present in population databases (rs756474485, gnomAD 0.04%). This missense change has been observed in individual(s) with sudden death in infancy (PMID: 29907895). ClinVar contains an entry for this variant (Variation ID: 201579). 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. -

Nov 16, 2021

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Ala665Thr variant in SCN5A has been reported in one individual with sudden unexplained death in infancy (Stroh van Deventer PMID: 29907895). It has also been identified in 0.036% (11/30602) of South Asian chromosomes by gnomAD (http://gnomad.broadinstitute.org). Computational prediction tools and conservation analyses do not provide strong support for or against an impact to the protein. In summary, while the clinical significance of this variant is uncertain, its frequency suggests that it is more likely to be benign. ACMG/AMP Criteria applied: BS1_Supporting. -

Cardiac arrhythmia

Uncertain:2

Oct 22, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces alanine with threonine at codon 665 of the SCN5A protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an infant with sudden death (PMID: 29907895). This variant has been identified in 17/280364 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The relatively high frequency of this variant in the general population suggests that this variant is unlikely to be disease-causing. However, additional studies are necessary to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Dec 01, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Cardiomyopathy

Uncertain:1

Feb 24, 2022

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

SUDDEN INFANT DEATH SYNDROME;C1832680:Dilated cardiomyopathy 1E;C1837845:Sick sinus syndrome 1;C1859062:Long QT syndrome 3;C1879286:Progressive familial heart block, type 1A;C2751898:Ventricular fibrillation, paroxysmal familial, type 1;C3151464:Atrial fibrillation, familial, 10;C4551804:Brugada syndrome 1

Uncertain:1

Sep 23, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiovascular phenotype

Benign:1

Nov 16, 2023

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

CardioboostCm

Benign

0.0054

BayesDel_addAF

Benign

-0.081

BayesDel_noAF

Uncertain

-0.040

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.52

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

Eigen

Benign

0.17

Eigen_PC

Benign

0.17

FATHMM_MKL

Uncertain

0.96

LIST_S2

Benign

0.80

.;T;T;T;T;T;T;.;T

M_CAP

Pathogenic

0.67

MetaRNN

Benign

0.30

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

MetaSVM

Uncertain

0.22

MutationAssessor

Benign

1.8

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

PrimateAI

Uncertain

0.67

PROVEAN

Benign

-1.1

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

REVEL

Uncertain

0.55

Sift

Benign

0.16

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

Sift4G

Benign

0.62

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

Polyphen

0.95

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

Vest4

0.24

MutPred

0.29

Gain of glycosylation at A665 (P = 0.0132);Gain of glycosylation at A665 (P = 0.0132);Gain of glycosylation at A665 (P = 0.0132);Gain of glycosylation at A665 (P = 0.0132);Gain of glycosylation at A665 (P = 0.0132);Gain of glycosylation at A665 (P = 0.0132);Gain of glycosylation at A665 (P = 0.0132);Gain of glycosylation at A665 (P = 0.0132);Gain of glycosylation at A665 (P = 0.0132);

MVP

0.79

MPC

0.98

ClinPred

0.15

GERP RS

3.2

Varity_R

0.077

gMVP

0.77

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over