rs199473251

Positions:

• chr3-38556535-A-G

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_000335.5(SCN5A):​c.4340T>C​(p.Ile1447Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I1447L) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SCN5A NM_000335.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: 7.41

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM1: In a helix (size 30) in uniprot entity SCN5A_HUMAN there are 9 pathogenic changes around while only 0 benign (100%) in NM_000335.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-38556536-T-G is described in Lovd as [Pathogenic].
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SCN5A. . Gene score misZ 2.7504 (greater than the threshold 3.09). Trascript score misZ 4.8279 (greater than threshold 3.09). GenCC has associacion of gene with 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.98

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SCN5A	NM_001099404.2	c.4343T>C	p.Ile1448Thr	missense_variant	25/28	ENST00000413689.6	NP_001092874.1
SCN5A	NM_000335.5	c.4340T>C	p.Ile1447Thr	missense_variant	25/28	ENST00000423572.7	NP_000326.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SCN5A	ENST00000413689.6	c.4343T>C	p.Ile1448Thr	missense_variant	25/28	5	NM_001099404.2	ENSP00000410257.1
SCN5A	ENST00000423572.7	c.4340T>C	p.Ile1447Thr	missense_variant	25/28	1	NM_000335.5	ENSP00000398266.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 36

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Nov 04, 2019

Variant summary: SCN5A c.4343T>C (p.Ile1448Thr) results in a non-conservative amino acid change located in the Ion transport domain (IPR005821) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 248530 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.4343T>C has been reported in the literature in individuals affected with Brugada Syndrome (Kapplinger_2016, Walsh_2014). These reports however, do not provide unequivocal conclusions about association of the variant with Brugada Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Different variants affecting the same codon (p.I1448L and p.I1448N) have been reported in patients in HGMD database. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Brugada syndrome Other:1

not provided, no classification provided

literature only

Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust

-

This variant has been reported as associated with Brugada syndrome in the following publications (PMID:20129283). 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	Benign	0.29
CardioboostCm	Uncertain	0.10
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.94	.;.;.;.;.;D;.;.;.
Eigen	Uncertain	0.35
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Benign	0.82	.;T;T;T;T;T;T;.;T
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.3	.;.;.;.;.;M;.;.;.
PrimateAI	Uncertain	0.64	T
PROVEAN	Uncertain	-3.4	D;D;D;D;D;D;D;D;D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0010	D;D;D;D;D;D;D;D;D
Sift4G	Uncertain	0.025	D;D;D;D;D;D;D;D;D
Polyphen		0.39	B;B;.;B;.;P;P;.;.
Vest4		0.93
MutPred		0.90		.;.;Loss of stability (P = 0.0178);.;.;Loss of stability (P = 0.0178);.;.;.;
MVP		0.96
MPC		0.90
ClinPred		0.99	D
GERP RS		4.3
Varity_R		0.80
gMVP		0.95

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: rs199473251; hg19: chr3-38598026;