rs886041805

chr17-63941506-C-Achr17-63941506-C-T

Variant summary

Our verdict is Pathogenic. Variant got 20 ACMG points: 20P and 0B. PS1_Very_Strong PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_000334.4(SCN4A):c.4776G>T(p.Met1592Ile) 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 Pathogenic (★). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M1592V) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: SCN4A NM_000334.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.91

Genes affected

SCN4A (HGNC:10591): (sodium voltage-gated channel alpha subunit 4) Voltage-gated sodium channels are transmembrane glycoprotein complexes composed of a large alpha subunit with 24 transmembrane domains and one or more regulatory beta subunits. They are responsible for the generation and propagation of action potentials in neurons and muscle. This gene encodes one member of the sodium channel alpha subunit gene family. It is expressed in skeletal muscle, and mutations in this gene have been linked to several myotonia and periodic paralysis disorders. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 20 ACMG points.

• PS1: Transcript NM_000334.4 (SCN4A) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar as 427072
• PM1: In a transmembrane_region Helical; Name=S6 of repeat IV (size 22) in uniprot entity SCN4A_HUMAN there are 8 pathogenic changes around while only 1 benign (89%) in NM_000334.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-63941508-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 5897.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.948
• PP5: Variant 17-63941506-C-A is Pathogenic according to our data. Variant chr17-63941506-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 280637.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SCN4A	NM_000334.4	c.4776G>T	p.Met1592Ile	missense_variant	24/24	ENST00000435607.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SCN4A	ENST00000435607.3	c.4776G>T	p.Met1592Ile	missense_variant	24/24	1	NM_000334.4	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 24, 2016

The M1592I variant in the SCN4A gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. The M1592I variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The M1592I variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. This substitution occurs at a position that is conserved across species. In silico analysis predicts this variant is probably damaging to the protein structure/function. A missense variant in the same residue (M1592V) has been reported in the Human Gene Mutation Database in association with hyperkalemic periodic paralysis (Stenson et al., 2014), supporting the functional importance of this residue. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.50
Cadd	Uncertain	26
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	D
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.40	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.87	D
PROVEAN	Uncertain	-3.3	D
REVEL	Pathogenic	0.94
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0090	D
Polyphen		1.0	D
Vest4		0.88
MutPred		0.77		Gain of catalytic residue at M1592 (P = 0.0061);
MVP		0.96
MPC		0.95
ClinPred		0.99	D
GERP RS		3.9
Varity_R		0.93
gMVP		0.92

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: rs886041805; hg19: chr17-62018866;