17-63947896-G-C

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PP2PP3_Moderate

The NM_000334.4(SCN4A):c.3312C>G(p.Ile1104Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000335 in 1,613,324 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. I1104V) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000034 ( 0 hom. )

Consequence

SCN4A
NM_000334.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: -0.507

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: Uncertain_significance. The variant received 3 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.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.915

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN4A	NM_000334.4 link	c.3312C>G	p.Ile1104Met	missense_variant	Exon 17 of 24	ENST00000435607.3	NP_000325.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN4A	ENST00000435607.3 link	c.3312C>G	p.Ile1104Met	missense_variant	Exon 17 of 24	1	NM_000334.4	ENSP00000396320.1
SCN4A	ENST00000584310.1 link	n.*58C>G		downstream_gene_variant		4

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152220

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000401

AC:

AN:

249218

AF XY:

0.0000222

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000886

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000342

AC:

AN:

1461104

Hom.:

Cov.:

AF XY:

0.0000275

AC XY:

AN XY:

726828

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33460

American (AMR)

AF:

0.00

AC:

AN:

44668

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26096

East Asian (EAS)

AF:

0.00

AC:

AN:

39678

South Asian (SAS)

AF:

0.00

AC:

AN:

86208

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53386

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5700

European-Non Finnish (NFE)

AF:

0.0000432

AC:

AN:

1111574

Other (OTH)

AF:

0.0000331

AC:

AN:

60334

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

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

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152220

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74376

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41454

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

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:

0.0000434

Hom.:

Bravo

AF:

0.0000189

ExAC

AF:

0.0000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000594

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Jun 24, 2022

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.3312C>G (p.I1104M) alteration is located in exon 17 (coding exon 17) of the SCN4A gene. This alteration results from a C to G substitution at nucleotide position 3312, causing the isoleucine (I) at amino acid position 1104 to be replaced by a methionine (M). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Hyperkalemic periodic paralysis

Uncertain:1

Aug 21, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 1104 of the SCN4A protein (p.Ile1104Met). This variant is present in population databases (rs779189351, gnomAD 0.009%). This variant has not been reported in the literature in individuals affected with SCN4A-related conditions. ClinVar contains an entry for this variant (Variation ID: 1045484). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt SCN4A protein function with a positive predictive value of 95%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.93

BayesDel_addAF

Pathogenic

0.22

BayesDel_noAF

Pathogenic

0.28

CADD

Benign

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.97

Eigen

Benign

0.15

Eigen_PC

Benign

-0.12

FATHMM_MKL

Benign

0.38

LIST_S2

Uncertain

0.97

M_CAP

Pathogenic

0.66

MetaRNN

Pathogenic

0.91

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.3

PhyloP100

-0.51

PrimateAI

Uncertain

0.78

PROVEAN

Uncertain

-2.9

REVEL

Pathogenic

0.84

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Vest4

0.84

ClinPred

0.99

GERP RS

-2.7

Varity_R

0.93

gMVP

0.83

Mutation Taster

=46/54

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.050

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