NM_000334.4:c.355G>A

Variant names:

Variant summary

Our verdict is Benign. The variant received -19 ACMG points: 1P and 20B. PP2BP4_StrongBP6_Very_StrongBS1BS2

The NM_000334.4(SCN4A):c.355G>A(p.Val119Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00287 in 1,613,924 control chromosomes in the GnomAD database, including 14 homozygotes. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0023 ( 3 hom., cov: 32)

Exomes 𝑓: 0.0029 ( 11 hom. )

Consequence

SCN4A
NM_000334.4 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:14

Conservation

PhyloP100: -0.0950

Publications

8 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: Benign. The variant received -19 ACMG points.

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.

BP4

Computational evidence support a benign effect (MetaRNN=0.013251126).

BP6

Variant 17-63972389-C-T is Benign according to our data. Variant chr17-63972389-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 324552.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.00226 (344/152266) while in subpopulation NFE AF = 0.00382 (260/68008). AF 95% confidence interval is 0.00344. There are 3 homozygotes in GnomAd4. There are 168 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High Homozygotes in GnomAd4 at 3 AR,AD gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN4A	NM_000334.4 link	c.355G>A	p.Val119Ile	missense_variant	Exon 2 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.355G>A	p.Val119Ile	missense_variant	Exon 2 of 24	1	NM_000334.4	ENSP00000396320.1		P35499

Frequencies

GnomAD3 genomes

AF:

0.00226

AC:

344

AN:

152148

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000580

Gnomad AMI

AF:

0.00329

Gnomad AMR

AF:

0.00190

Gnomad ASJ

AF:

0.000288

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00145

Gnomad FIN

AF:

0.00170

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.00382

Gnomad OTH

AF:

0.000479

GnomAD2 exomes

AF:

0.00236

AC:

588

AN:

249122

AF XY:

0.00235

show subpopulations

Gnomad AFR exome

AF:

0.000452

Gnomad AMR exome

AF:

0.000754

Gnomad ASJ exome

AF:

0.000298

Gnomad EAS exome

AF:

0.0000556

Gnomad FIN exome

AF:

0.00167

Gnomad NFE exome

AF:

0.00398

Gnomad OTH exome

AF:

0.00215

GnomAD4 exome

AF:

0.00293

AC:

4281

AN:

1461658

Hom.:

Cov.:

AF XY:

0.00286

AC XY:

2078

AN XY:

727114

show subpopulations

African (AFR)

AF:

0.000508

AC:

AN:

33480

American (AMR)

AF:

0.000805

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.000230

AC:

AN:

26132

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00180

AC:

155

AN:

86250

European-Finnish (FIN)

AF:

0.00202

AC:

108

AN:

53400

Middle Eastern (MID)

AF:

0.00208

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00340

AC:

3775

AN:

1111836

Other (OTH)

AF:

0.00283

AC:

171

AN:

60372

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.481

Heterozygous variant carriers

243

486

730

973

1216

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

130

260

390

520

650

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00226

AC:

344

AN:

152266

Hom.:

Cov.:

AF XY:

0.00226

AC XY:

168

AN XY:

74452

show subpopulations

African (AFR)

AF:

0.000578

AC:

AN:

41536

American (AMR)

AF:

0.00189

AC:

AN:

15306

Ashkenazi Jewish (ASJ)

AF:

0.000288

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00145

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00170

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00340

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00382

AC:

260

AN:

68008

Other (OTH)

AF:

0.000474

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.499

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00278

Hom.:

Bravo

AF:

0.00191

TwinsUK

AF:

0.00431

AC:

ALSPAC

AF:

0.00130

AC:

ESP6500AA

AF:

0.000463

AC:

ESP6500EA

AF:

0.00422

AC:

ExAC

AF:

0.00259

AC:

314

Asia WGS

AF:

0.000577

AC:

AN:

3478

EpiCase

AF:

0.00305

EpiControl

AF:

0.00279

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:14

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:5

Feb 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

SCN4A: BS2 -

Aug 25, 2020

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Breakthrough Genomics, Breakthrough Genomics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:not provided

- -

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

not specified

Benign:2

May 01, 2020

Genetic Services Laboratory, University of Chicago

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

DNA sequence analysis of the SCN4A gene demonstrated a sequence change, c.355G>A, in exon 2 that results in an amino acid change, p.Val119Ile. This sequence change does not appear to have been previously described in patients with SCN4A-related disorders and has been described in the gnomAD database with a high population frequency of 0.41% in the non-Finnish European subpopulation (dbSNP rs41280110); it has been observed in one individual in the homozygous state. The p.Val119Ile change affects a poorly conserved amino acid residue located in a domain of the SCN4A protein that is not known to be functional. The p.Val119Ile substitution appears to be benign using several in-silico pathogenicity prediction tools (SIFT, PolyPhen2, Align GVGD, REVEL). Due to these contrasting evidences and the lack of functional studies, the clinical significance of the p.Val119Ile change remains unknown at this time. -

Sep 24, 2021

Athena Diagnostics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Familial hyperkalemic periodic paralysis

Benign:2

Jan 30, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Hypokalemic periodic paralysis, type 2

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Paramyotonia congenita of Von Eulenburg

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Potassium-aggravated myotonia

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Paramyotonia congenita of Von Eulenburg;C0238357:Familial hyperkalemic periodic paralysis;C2750061:Hypokalemic periodic paralysis, type 2;C2931826:Potassium-aggravated myotonia;C3280112:Congenital myasthenic syndrome 16;C3714580:Hypokalemic periodic paralysis, type 1

Benign:1

Nov 09, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Congenital myasthenic syndrome 16

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.062

BayesDel_addAF

Benign

-0.48

BayesDel_noAF

Benign

-0.46

CADD

Benign

0.0090

(source)

DANN

Benign

0.89

DEOGEN2

Benign

0.29

Eigen

Benign

-1.8

Eigen_PC

Benign

-1.7

FATHMM_MKL

Benign

0.058

LIST_S2

Benign

0.71

M_CAP

Benign

0.015

MetaRNN

Benign

0.013

MetaSVM

Benign

-0.36

MutationAssessor

Benign

-1.2

PhyloP100

-0.095

PrimateAI

Benign

0.24

PROVEAN

Benign

-0.28

REVEL

Benign

0.23

Sift

Benign

0.37

Sift4G

Benign

0.10

Polyphen

0.0

Vest4

0.11

MVP

0.49

MPC

0.20

ClinPred

0.00078

GERP RS

-0.98

Varity_R

0.049

gMVP

0.35

Mutation Taster

=100/0

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over