3-38550602-C-T

Variant names:

• chr3-38550602-C-T
• rs137854603
• NM_001099404.2:c.5770G>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PS3 BP4

The NM_000335.5(SCN5A):​c.5767G>A​(p.Ala1923Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0000254 in 1,613,950 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). ClinVar reports functional evidence for this variant: "SCV000916016: Functional studies in Xenopus oocytes demonstrated that the variant significantly affected the inward sodium current causing an increase during the action potential upstroke (Rook et al. 1999). Tan et al. (200) demonstrated that the p.Ala1924Thr increased the rate of fast activation of the sodium channel whilst inhibiting the slow activation induced by the calcium-dependent binding of calmodulin.". Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A1923V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000025 (0 hom.)
• Consequence: SCN5A NM_000335.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:5 B:1 O:1
• Conservation: PhyloP100: 6.16
• Publications: 34 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: Uncertain_significance. The variant received 3 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV000916016: Functional studies in Xenopus oocytes demonstrated that the variant significantly affected the inward sodium current causing an increase during the action potential upstroke (Rook et al. 1999). Tan et al. (200) demonstrated that the p.Ala1924Thr increased the rate of fast activation of the sodium channel whilst inhibiting the slow activation induced by the calcium-dependent binding of calmodulin.
• BP4: Computational evidence support a benign effect (MetaRNN=0.39713567).

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.5770G>A	p.Ala1924Thr	missense	Exon 28 of 28	NP_001092874.1	H9KVD2
	SCN5A	NM_000335.5	MANE Select	c.5767G>A	p.Ala1923Thr	missense	Exon 28 of 28	NP_000326.2
	SCN5A	NM_198056.3		c.5770G>A	p.Ala1924Thr	missense	Exon 28 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.5770G>A	p.Ala1924Thr	missense	Exon 28 of 28	ENSP00000410257.1	H9KVD2
	SCN5A	ENST00000423572.7	TSL:1 MANE Select	c.5767G>A	p.Ala1923Thr	missense	Exon 28 of 28	ENSP00000398266.2	Q14524-2
	SCN5A	ENST00000333535.9	TSL:1	c.5770G>A	p.Ala1924Thr	missense	Exon 28 of 28	ENSP00000328968.4	Q14524-1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152248 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.000864

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000602 AC: 15 AN: 249238 AF XY: 0.0000444

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00119

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000885

Gnomad OTH exome AF: 0.000165

GnomAD4 exome AF: 0.0000253 AC: 37 AN: 1461702 Hom.: 0 Cov.: 32 AF XY: 0.0000234 AC XY: 17 AN XY: 727136

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.0000447 AC: 2 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.000918 AC: 24 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53394

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000540 AC: 6 AN: 1111868

Other (OTH) AF: 0.0000828 AC: 5 AN: 60374

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152248 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74382

African (AFR) AF: 0.00 AC: 0 AN: 41464

American (AMR) AF: 0.0000654 AC: 1 AN: 15286

Ashkenazi Jewish (ASJ) AF: 0.000864 AC: 3 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4838

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10630

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68048

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.000126 Hom.: 0

Bravo AF: 0.0000416

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000119 AC: 1

ExAC AF: 0.0000413 AC: 5

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
2	-	-	Brugada syndrome 1 (2)
-	1	1	not provided (2)
-	1	-	Cardiac arrhythmia (1)
-	1	-	Cardiovascular phenotype (1)
-	1	-	Long QT syndrome;C1142166:Brugada syndrome (1)
-	1	-	not specified (1)
-	-	-	Brugada syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.36
CardioboostArm	Uncertain	0.73
CardioboostCm	Benign	0.042
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Pathogenic	0.25
CADD	Uncertain	24
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.57	D
Eigen	Uncertain	0.60
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.85	D
M_CAP	Pathogenic	0.43	D
MetaRNN	Benign	0.40	T
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.6	M
PhyloP100		6.2
PrimateAI	Uncertain	0.58	T
PROVEAN	Benign	-1.2	N
REVEL	Pathogenic	0.74
Sift	Benign	0.058	T
Sift4G	Benign	0.26	T
Polyphen		0.97	D
Vest4		0.59
MVP		0.89
MPC		1.4
ClinPred		0.28	T
GERP RS		4.9
Varity_R		0.28
gMVP		0.59
Mutation Taster		=8/92	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs137854603; hg19: chr3-38592093;