chr3-38560418-T-C

Variant names:

• chr3-38560418-T-C
• rs28937317
• NM_001099404.2:c.3974A>G

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PS3 PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_000335.5(SCN5A):​c.3971A>G​(p.Asn1324Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,459,700 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 Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV005398136: Compared to WT cells, HEK293 cells transfected with the p.(Asn1325Ser) mutant transcript demonstrated both increased availability of mutant channels and late sodium current which were reversed when treated with the sodium current inhibitor, mexiletine. However, patch clamp assays have been shown to be unreliable" and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N1324K) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: SCN5A NM_000335.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6 O:1
• Conservation: PhyloP100: 7.95
• Publications: 44 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: Orphanet, ClinGen
• Brugada syndrome 1

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

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

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

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

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

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• progressive familial heart block, type 1A

  Inheritance: AD, SD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics
• sick sinus syndrome 1

  Inheritance: AR, AD Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
• 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
• congenital heart disease

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

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 20 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV005398136: Compared to WT cells, HEK293 cells transfected with the p.(Asn1325Ser) mutant transcript demonstrated both increased availability of mutant channels and late sodium current which were reversed when treated with the sodium current inhibitor, mexiletine. However, patch clamp assays have been shown to be unreliable; therefore results from these studies are used with caution during variant classification (PMID: 32848785).; SCV002623130: "In addition, this alteration has been shown to have an impact on sodium channel current (Dumaine R, Circ. Res. 1996 May; 78(5):916-24; Tian XL, Cardiovasc. Res. 2004 Feb;61(2):256-67; Yong SL, Biochem. Biophys. Res. Commun. 2007 Jan; 352(2):378-83)."; SCV001397968: Experimental studies have shown that this missense change affects SCN5A function (PMID: 8620612, 8917568, 19762097).; SCV003933403: Published functional studies demonstrate a damaging effect using patch clamp studies that showed that N1325S results in abnormal channel current, and N1325S mouse cardiomyocytes showed contractile dysfunction, possibly caused by aberrant cardiomyocyte apoptosis (Dumaine et al., 1996; Wang et al., 1996; Tian et al., 2004; Yong et al., 2007; Zhang et al., 2011); SCV006087076: The variant impacts protein function (e.g. Zhang_2011, Wang_1996). PMID: 28412158, 8541846, 8917568, 19762097
• PM1: In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 uncertain in NM_000335.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988
• PP5: Variant 3-38560418-T-C is Pathogenic according to our data. Variant chr3-38560418-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 9370.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000335.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN5A	NM_001099404.2	MANE Plus Clinical	c.3974A>G	p.Asn1325Ser	missense	Exon 23 of 28	NP_001092874.1	H9KVD2
	SCN5A	NM_000335.5	MANE Select	c.3971A>G	p.Asn1324Ser	missense	Exon 23 of 28	NP_000326.2
	SCN5A	NM_198056.3		c.3974A>G	p.Asn1325Ser	missense	Exon 23 of 28	NP_932173.1	Q14524-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN5A	ENST00000413689.6	TSL:5 MANE Plus Clinical	c.3974A>G	p.Asn1325Ser	missense	Exon 23 of 28	ENSP00000410257.1	H9KVD2
	SCN5A	ENST00000423572.7	TSL:1 MANE Select	c.3971A>G	p.Asn1324Ser	missense	Exon 23 of 28	ENSP00000398266.2	Q14524-2
	SCN5A	ENST00000333535.9	TSL:1	c.3974A>G	p.Asn1325Ser	missense	Exon 23 of 28	ENSP00000328968.4	Q14524-1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1459700 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 725988

African (AFR) AF: 0.00 AC: 0 AN: 33458

American (AMR) AF: 0.00 AC: 0 AN: 44682

Ashkenazi Jewish (ASJ) AF: 0.0000386 AC: 1 AN: 25928

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 85904

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53300

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1110668

Other (OTH) AF: 0.00 AC: 0 AN: 60312

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	Long QT syndrome 3 (2)
2	-	-	not provided (2)
1	-	-	Cardiovascular phenotype (1)
1	-	-	Long QT syndrome (1)
-	-	-	Congenital long QT syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
CardioboostArm	Pathogenic	1.0
CardioboostCm	Uncertain	0.20
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.10
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D
Eigen	Uncertain	0.55
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.80	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.7	M
PhyloP100		7.9
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-4.2	D
REVEL	Pathogenic	0.92
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.035	D
Polyphen		0.59	P
Vest4		0.86
MutPred		0.93		Loss of MoRF binding (P = 0.1367)
MVP		0.97
MPC		1.3
ClinPred		0.99	D
GERP RS		4.1
Varity_R		0.61
gMVP		0.94
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs28937317; hg19: chr3-38601909;