3-38609850-A-T

Position:

• chr3-38609850-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_001099404.2(SCN5A):​c.818T>A​(p.Met273Lys) 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. M273T) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SCN5A NM_001099404.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.32

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.

• PM2: Very rare variant in population databases, with high coverage
• 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 4.7729 (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, 0.869

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SCN5A	NM_001099404.2	c.818T>A	p.Met273Lys	missense_variant	7/28	ENST00000413689.6
SCN5A	NM_000335.5	c.818T>A	p.Met273Lys	missense_variant	7/28	ENST00000423572.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SCN5A	ENST00000413689.6	c.818T>A	p.Met273Lys	missense_variant	7/28	5	NM_001099404.2	P4
SCN5A	ENST00000423572.7	c.818T>A	p.Met273Lys	missense_variant	7/28	1	NM_000335.5	A1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 24, 2016

The p.M273K variant (also known as c.818T>A), located in coding exon 6 of the SCN5A gene, results from a T to A substitution at nucleotide position 818. The methionine at codon 273 is replaced by lysine, an amino acid with some similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6472 samples (12944 alleles) with coverage at this position. This amino acid position is highly 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	0.31
CardioboostCm	Uncertain	0.26
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.41
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.93	.;.;.;.;.;D;.;.;.
Eigen	Uncertain	0.53
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.83	.;T;T;T;T;T;T;.;T
M_CAP	Pathogenic	0.47	D
MetaRNN	Pathogenic	0.87	D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.88	D
MutationAssessor	Benign	-0.65	.;N;.;.;.;N;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D
PrimateAI	Pathogenic	0.88	D
PROVEAN	Uncertain	-3.5	D;D;D;D;D;D;D;D;D
REVEL	Pathogenic	0.89
Sift	Benign	0.23	T;T;T;T;T;T;T;T;T
Sift4G	Benign	0.15	T;T;T;T;T;T;T;T;T
Polyphen		0.99	D;B;.;D;.;D;D;.;.
Vest4		0.94
MutPred		0.66		Gain of MoRF binding (P = 0.0385);Gain of MoRF binding (P = 0.0385);Gain of MoRF binding (P = 0.0385);Gain of MoRF binding (P = 0.0385);Gain of MoRF binding (P = 0.0385);Gain of MoRF binding (P = 0.0385);Gain of MoRF binding (P = 0.0385);Gain of MoRF binding (P = 0.0385);Gain of MoRF binding (P = 0.0385);
MVP		0.85
MPC		1.4
ClinPred		0.97	D
GERP RS		5.3
Varity_R		0.82
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs200076065; hg19: chr3-38651341;