chr3-38587437-C-T

Variant names:

• chr3-38587437-C-T
• rs566251672
• NM_001099404.2:c.2399G>A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP2

The NM_000335.5(SCN5A):​c.2399G>A​(p.Arg800His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000018 in 1,613,570 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000018 (0 hom.)
• Consequence: SCN5A NM_000335.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:7
• Conservation: PhyloP100: 0.794

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM1: In a repeat II (size 270) in uniprot entity SCN5A_HUMAN there are 47 pathogenic changes around while only 2 benign (96%) in NM_000335.5
• 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN5A	NM_001099404.2	c.2399G>A	p.Arg800His	missense_variant	Exon 15 of 28	ENST00000413689.6	NP_001092874.1
SCN5A	NM_000335.5	c.2399G>A	p.Arg800His	missense_variant	Exon 15 of 28	ENST00000423572.7	NP_000326.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN5A	ENST00000413689.6	c.2399G>A	p.Arg800His	missense_variant	Exon 15 of 28	5	NM_001099404.2	ENSP00000410257.1
SCN5A	ENST00000423572.7	c.2399G>A	p.Arg800His	missense_variant	Exon 15 of 28	1	NM_000335.5	ENSP00000398266.2

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152156 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: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000943

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000161 AC: 4 AN: 248516 Hom.: 0 AF XY: 0.0000148 AC XY: 2 AN XY: 134788

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000355

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000185 AC: 27 AN: 1461294 Hom.: 0 Cov.: 31 AF XY: 0.0000193 AC XY: 14 AN XY: 726878

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.0000749

Gnomad4 NFE exome AF: 0.0000162

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152276 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74454

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000943

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000526 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cardiac arrhythmia Uncertain:2

Jul 10, 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 histidine at codon 800 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). An in vitro functional study has shown that this variant causes a shorter recovery time from inactivation in the mutant channel (PMID: 32323320). This variant has been reported in an individual affected with hypertrophic cardiomyopathy (PMID: 26281194) and in another individual with short-coupled variant of torsades de pointes (PMID: 32323320). This variant has been identified in 5/279914 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Feb 23, 2023

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 histidine at codon 800 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). An in vitro functional study has shown that this variant causes a shorter recovery time from inactivation in the mutant channel (PMID: 32323320). This variant has been reported in an individual affected with hypertrophic cardiomyopathy (PMID: 26281194) and in another individual with short-coupled variant of torsades de pointes (PMID: 32323320). This variant has been identified in 5/279914 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

not specified Uncertain:1

Sep 24, 2018

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: SCN5A c.2399G>A (p.Arg800His) results in a non-conservative amino acid change located in the Ion transport domain of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.8e-05 in 276510 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.2399G>A has been reported in the literature in individuals affected with Arrhythmia (Ghouse_2015, Josifovska_2018). In particular, one patient with a rare form of asymmetrical left ventricle hypertrophy with mild left ventricular outflow obstruction (intra-ventricle gradient) was found to be digenic carrying the variant of interest, along with another CACNA1C variant, p.Arg514Gly. The child's parent carried the variant of interest and was indicated to be unaffected (Josifovska_2018). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two ClinVar submissions from clinical diagnostic laboratories (evaluation after 2014) cites the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Arrhythmogenic right ventricular cardiomyopathy Uncertain:1

Mar 26, 2015

Blueprint Genetics

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

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

Feb 24, 2024

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 histidine, which is basic and polar, at codon 800 of the SCN5A protein (p.Arg800His). This variant is present in population databases (rs566251672, gnomAD 0.004%). This missense change has been observed in individual(s) with clinical features of long QT syndrome (PMID: 26159999, 32323320). ClinVar contains an entry for this variant (Variation ID: 222807). 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. Experimental studies have shown that this missense change affects SCN5A function (PMID: 32323320). 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

Oct 18, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R800H variant (also known as c.2399G>A), located in coding exon 14 of the SCN5A gene, results from a G to A substitution at nucleotide position 2399. The arginine at codon 800 is replaced by histidine, an amino acid with highly similar properties. This alteration has been reported in an exome cohort and in an individual with features of hypertrophic cardiomyopathy (HCM), who also carried a variant in another cardiac-related gene (Ghouse J et al. Eur. Heart J., 2015 Oct;36:2523-9; Josifovska S et al. Biotechnology & Biotechnological Equipment. 2018 Feb;679-685). This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
CardioboostCm	Benign	0.040
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Pathogenic	0.14
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.66	.;.;.;.;.;D;.;.;.
Eigen	Uncertain	0.29
Eigen_PC	Uncertain	0.32
FATHMM_MKL	Benign	0.74	D
LIST_S2	Uncertain	0.89	.;D;D;D;D;D;D;.;D
M_CAP	Pathogenic	0.60	D
MetaRNN	Uncertain	0.47	T;T;T;T;T;T;T;T;T
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Benign	0.95	.;L;.;.;.;L;.;.;.
PrimateAI	Uncertain	0.54	T
PROVEAN	Benign	-0.94	N;N;N;N;N;N;N;N;N
REVEL	Uncertain	0.56
Sift	Uncertain	0.017	D;T;D;D;D;D;T;D;D
Sift4G	Benign	0.11	T;T;T;T;T;T;T;T;T
Polyphen		0.96	D;D;.;D;.;D;D;.;.
Vest4		0.43
MutPred		0.65		Loss of MoRF binding (P = 0.0479);Loss of MoRF binding (P = 0.0479);Loss of MoRF binding (P = 0.0479);Loss of MoRF binding (P = 0.0479);Loss of MoRF binding (P = 0.0479);Loss of MoRF binding (P = 0.0479);Loss of MoRF binding (P = 0.0479);Loss of MoRF binding (P = 0.0479);Loss of MoRF binding (P = 0.0479);
MVP		0.83
MPC		1.2
ClinPred		0.61	D
GERP RS		4.4
Varity_R		0.16
gMVP		0.83

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

Other links and lift over

dbSNP: rs566251672; hg19: chr3-38628928;