17-63941894-C-T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1PM5PP2PP5_Moderate

The NM_000334.4(SCN4A):c.4388G>A(p.Arg1463His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000143 in 1,613,344 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1463S) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000015 ( 0 hom. )

Consequence

SCN4A
NM_000334.4 missense

Scores

Clinical Significance

Pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 2.64

Publications

1 publications found

Variant links:

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]

SCN4A Gene-Disease associations (from GenCC):

hyperkalemic periodic paralysis
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, Orphanet
paramyotonia congenita of Von Eulenburg
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, Orphanet
SCN4A-related myopathy, autosomal recessive
Inheritance: AR Classification: DEFINITIVE Submitted by: Illumina, ClinGen
hypokalemic periodic paralysis, type 2
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
potassium-aggravated myotonia
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
congenital myasthenic syndrome 16
Inheritance: AR Classification: STRONG, LIMITED Submitted by: PanelApp Australia, Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
congenital myopathy
Inheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp
congenital myopathy 22A, classic
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
acetazolamide-responsive myotonia
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
hypokalemic periodic paralysis
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
myotonia fluctuans
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
myotonia permanens
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
postsynaptic congenital myasthenic syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

SCN4A links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_000334.4

PM5

Other missense variant is known to change same aminoacid residue: Variant chr17-63941895-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 654578.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 97 curated pathogenic missense variants (we use a threshold of 10). The gene has 19 curated benign missense variants. Gene score misZ: 1.5606 (below the threshold of 3.09). Trascript score misZ: 2.2224 (below the threshold of 3.09). GenCC associations: The gene is linked to congenital myasthenic syndrome 16, paramyotonia congenita of Von Eulenburg, hyperkalemic periodic paralysis, hypokalemic periodic paralysis, type 2, congenital myopathy, hypokalemic periodic paralysis, SCN4A-related myopathy, autosomal recessive, congenital myopathy 22A, classic, potassium-aggravated myotonia, postsynaptic congenital myasthenic syndrome, myotonia fluctuans, myotonia permanens, acetazolamide-responsive myotonia.

PP5

Variant 17-63941894-C-T is Pathogenic according to our data. Variant chr17-63941894-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 642244.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN4A	NM_000334.4 link	c.4388G>A	p.Arg1463His	missense_variant	Exon 24 of 24	ENST00000435607.3	NP_000325.4	P35499

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN4A	ENST00000435607.3 link	c.4388G>A	p.Arg1463His	missense_variant	Exon 24 of 24	1	NM_000334.4	ENSP00000396320.1		P35499

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152218

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000800

AC:

AN:

249924

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000885

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000151

AC:

AN:

1461008

Hom.:

Cov.:

AF XY:

0.00000826

AC XY:

AN XY:

726646

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33470

American (AMR)

AF:

0.0000224

AC:

AN:

44714

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39682

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53380

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000189

AC:

AN:

1111270

Other (OTH)

AF:

0.00

AC:

AN:

60350

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.482

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000656

AC:

AN:

152336

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74490

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41576

American (AMR)

AF:

0.00

AC:

AN:

15308

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68036

Other (OTH)

AF:

0.00

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Familial hyperkalemic periodic paralysis

Pathogenic:1

Jan 17, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 1463 of the SCN4A protein (p.Arg1463His). This variant is present in population databases (rs771340029, gnomAD 0.003%). This missense change has been observed in individuals with clinical features of paramyotonia congenita (PMID: 29606556, 33670307; Invitae). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 642244). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SCN4A protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects SCN4A function (PMID: 33670307). This variant disrupts the p.Arg1463 amino acid residue in SCN4A. Other variant(s) that disrupt this residue have been observed in individuals with SCN4A-related conditions (PMID: 29605429; Invitae), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.76

BayesDel_addAF

Uncertain

0.13

BayesDel_noAF

Uncertain

0.040

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.96

Eigen

Uncertain

0.56

Eigen_PC

Uncertain

0.42

FATHMM_MKL

Uncertain

0.81

LIST_S2

Uncertain

0.92

M_CAP

Pathogenic

0.52

MetaRNN

Uncertain

0.71

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.4

PhyloP100

2.6

PrimateAI

Pathogenic

0.83

PROVEAN

Uncertain

-3.8

REVEL

Pathogenic

0.76

Sift

Pathogenic

0.0

Sift4G

Uncertain

0.025

Polyphen

1.0

Vest4

0.34

MutPred

0.74

Loss of methylation at R1463 (P = 0.0316);

MVP

0.88

MPC

1.0

ClinPred

0.99

GERP RS

3.7

Varity_R

0.78

gMVP

0.77

Mutation Taster

=8/92

disease causing

(source)

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

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17-63941894-C-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over