3-38613772-C-T

Variant names:

• chr3-38613772-C-T
• rs199473071
• NM_000335.5:c.674G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM5 PP3_Strong PP5

The NM_000335.5(SCN5A):​c.674G>A​(p.Arg225Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000118 in 1,609,272 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. R225W) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000011 (0 hom.)
• Consequence: SCN5A NM_000335.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:6 U:6 O:1
• Conservation: PhyloP100: 7.91
• Publications: 18 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: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 13 uncertain in NM_000335.5
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-38613773-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 68032.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.991
• PP5: Variant 3-38613772-C-T is Pathogenic according to our data. Variant chr3-38613772-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 68033.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN5A	NM_000335.5	c.674G>A	p.Arg225Gln	missense_variant	Exon 6 of 28	ENST00000423572.7	NP_000326.2
SCN5A	NM_001099404.2	c.703+203G>A		intron_variant	Intron 6 of 27	ENST00000413689.6	NP_001092874.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN5A	ENST00000423572.7	c.674G>A	p.Arg225Gln	missense_variant	Exon 6 of 28	1	NM_000335.5	ENSP00000398266.2
SCN5A	ENST00000413689.6	c.703+203G>A		intron_variant	Intron 6 of 27	5	NM_001099404.2	ENSP00000410257.1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152182 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000192

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000166 AC: 4 AN: 241632 AF XY: 0.0000229

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000171

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000110 AC: 16 AN: 1456972 Hom.: 0 Cov.: 30 AF XY: 0.00000828 AC XY: 6 AN XY: 724256

African (AFR) AF: 0.0000599 AC: 2 AN: 33404

American (AMR) AF: 0.00 AC: 0 AN: 44154

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25998

East Asian (EAS) AF: 0.000177 AC: 7 AN: 39566

South Asian (SAS) AF: 0.0000118 AC: 1 AN: 85062

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53080

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00000451 AC: 5 AN: 1109726

Other (OTH) AF: 0.0000166 AC: 1 AN: 60220

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152300 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74468

African (AFR) AF: 0.00 AC: 0 AN: 41560

American (AMR) AF: 0.00 AC: 0 AN: 15296

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.000193 AC: 1 AN: 5194

South Asian (SAS) AF: 0.000207 AC: 1 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

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

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68020

Other (OTH) AF: 0.00 AC: 0 AN: 2108

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000340

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:6 Uncertain:6 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

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 Pathogenic:2

-

Juno Genomics, Hangzhou Juno Genomics, Inc

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PM2_Supporting+PS4_Moderate+PS3_Supporting+PM5 -

Mar 04, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Long QT syndrome 3 Pathogenic:2

Jun 21, 2022

Institute of Human Genetics, Clinical Exome/Genome Diagnostics Group, University Hospital Bonn

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 17, 2022

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

_x000D_ Criteria applied: PM5_STR, PS4_MOD, PS3_SUP, PP3 -

Brugada syndrome 1 Uncertain:2

Apr 04, 2024

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 28, 2019

Mendelics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiac arrhythmia Uncertain:2

Jul 29, 2024

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with glutamine at codon 225 of the SCN5A protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Functional studies have shown this variant mildly changes channel activation and channel availability (PMID: 24815523) and decreases peak sodium current density (PMID: 28779003, 35701104). This variant has been reported in individuals affected with Brugada syndrome (PMID: 33071830), long QT syndrome (PMID: 16922724, 32893267), idiopathic dilated cardiomyopathy (PMID: 28779003, 35284542), sudden unexplained death (PMID: 24631775, 29247119), and epilepsy (PMID: 31696929). This variant has been identified in 4/241632 chromosomes in the general population by the Genome Aggregation Database (gnomAD). A different missense variant occurring at the same codon, p.Arg225Trp (Clinvar variation ID: 68032) is known to be pathogenic, suggesting that arginine at this position is important for SCN5A protein function. The available clinical evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Jul 18, 2024

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with glutamine at codon 225 of the SCN5A protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function. Functional studies have shown this variant has a mild impact on sodium channel activation (PMID: 24815523) and results in a decreased peak sodium current density (PMID: 28779003, 35701104). This variant has been reported in individuals affected with long QT syndrome (PMID: 16922724, 32893267), idiopathic dilated cardiomyopathy (PMID: 28779003, 35284542), sudden unexplained death (PMID: 24631775, 29247119), and epilepsy (PMID: 31696929). This variant has been identified in 4/241632 chromosomes in the general population by the Genome Aggregation Database (gnomAD). A different missense variant occurring at the same codon, p.Arg225Trp, is known to be pathogenic (Clinvar variation ID: 68032), suggesting that arginine at this position is important for SCN5A protein function. The available clinical evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Dilated cardiomyopathy 1E Pathogenic:1

Dec 20, 2017

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

- -

not provided Pathogenic:1

Jun 18, 2025

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 24815523, 24631775, 29728395, 29247119, 33071830, 28779003, 35701104, 37461109, 16922724) -

Brugada syndrome Uncertain:1

Oct 27, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 225 of the SCN5A protein (p.Arg225Gln). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individual(s) with long QT syndrome, Brugada syndrome, dilated cardiomyopathy, or sudden death (PMID: 16922724, 28779003, 29247119, 33071830). ClinVar contains an entry for this variant (Variation ID: 68033). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on SCN5A function (PMID: 24815523, 28779003). This variant disrupts the p.Arg225 amino acid residue in SCN5A. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 12574143, 20031634, 24815523). 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. -

Cardiovascular phenotype Uncertain:1

Dec 23, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.674G>A (p.R225Q) alteration is located in exon 6 (coding exon 5) of the SCN5A gene. This alteration results from a G to A substitution at nucleotide position 674, causing the arginine (R) at amino acid position 225 to be replaced by a glutamine (Q). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Congenital long QT 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 Long QT syndrome in the following publications (PMID:16922724). 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	Pathogenic	0.98
CardioboostArm	Uncertain	0.12
CardioboostCm	Uncertain	0.36
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	31
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.99	.;D;.
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Pathogenic	4.1	H;H;.
PhyloP100		7.9
PROVEAN	Uncertain	-3.9	D;D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;D
Sift4G	Uncertain	0.0090	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.98
MutPred		0.99		Loss of MoRF binding (P = 0.0252);Loss of MoRF binding (P = 0.0252);Loss of MoRF binding (P = 0.0252);
MVP		0.99
ClinPred		0.88	D
GERP RS		4.3
Varity_R		0.94
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.15		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: rs199473071; hg19: chr3-38655263; COSMIC: COSV61120607; COSMIC: COSV61120607;