17-63943846-C-G

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM1PM5PP3_ModeratePP5_Very_Strong

The NM_000334.4(SCN4A):c.3917G>C(p.Gly1306Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000562 in 1,601,794 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G1306E) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

SCN4A
NM_000334.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:10O:1

Conservation

PhyloP100: 7.90

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 14 ACMG points.

PM1

In a topological_domain Cytoplasmic (size 62) in uniprot entity SCN4A_HUMAN there are 12 pathogenic changes around while only 0 benign (100%) in NM_000334.4

PM5

Other missense variant is known to change same aminoacid residue: Variant chr17-63943846-C-T is described in Lovd as [Pathogenic].

PP3

MetaRNN computational evidence supports a deleterious effect, 0.901

PP5

Variant 17-63943846-C-G is Pathogenic according to our data. Variant chr17-63943846-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 5908.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-63943846-C-G is described in Lovd as [Pathogenic]. Variant chr17-63943846-C-G is described in Lovd as [Likely_pathogenic]. Variant chr17-63943846-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN4A	NM_000334.4 link	c.3917G>C	p.Gly1306Ala	missense_variant	Exon 22 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.3917G>C	p.Gly1306Ala	missense_variant	Exon 22 of 24	1	NM_000334.4	ENSP00000396320.1		P35499

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152152

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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

GnomAD3 exomes

AF:

0.00000401

AC:

AN:

249512

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135334

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 SAS 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:

0.00000483

AC:

AN:

1449642

Hom.:

Cov.:

AF XY:

0.00000139

AC XY:

AN XY:

721982

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000636

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152152

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74332

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

ExAC

AF:

0.00000825

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:10Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:6

Feb 03, 2014

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 01, 2022

Institute for Clinical Genetics, University Hospital TU Dresden, University Hospital TU Dresden

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 14, 2023

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The frequency of this variant in the general population is consistent with pathogenicity (Genome Aggregation Database (gnomAD), Cambridge, MA (URL: http://gnomad.broadinstitute.org)). This variant has been identified in individuals with myotonia and segregates with disease in multiple families. At least one other missense variant at this codon is considered to be pathogenic or likely pathogenic, suggesting this variant may also cause disease. Assessment of experimental evidence suggests this variant results in abnormal protein function. (PMID: 7473241, 8740371, 16392038). -

Feb 25, 2021

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Published functional studies indicate that this variant impairs fast inactivation as compared to wild type (Lerche et al., 1993); Predicted to be within the intracellular loop between the third and fourth homologous domain; Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; In-silico analysis, which includes splice predictors and evolutionary conservation, is inconclusive as to whether the variant alters gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; This variant is associated with the following publications: (PMID: 32369273, 25525159, 7980103, 8308722, 31307605, 29774303, 28877545, 32849172, 32670189, 26080010, 31544778, 26885337, 32660787, 32528171) -

Mar 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

SCN4A: PS4, PM1, PM2, PM5, PP3, PS3:Supporting -

Nov 24, 2022

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

SCN4A-related channelopathy

Pathogenic:1

Nov 04, 2024

Molecular Genetics, Royal Melbourne Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change in SCN4A is predicted to replace glycine with alanine at codon 1306, p.(Gly1306Ala). The glycine residue is highly conserved (100 vertebrates, Multiz Alignments), and is located in the cytoplasmic ion transporter region. There is a moderate physicochemical difference between glycine and alanine. The highest population minor allele frequency in the population database gnomAD v4.1 is 0.001% (1/74,674 alleles) in the African/African-American population. This variant has been reported in multiple unrelated probands with myotonia and segregates with disease in multiple families (PMID: 15389891, 28325641, 32670189, 26080010, 33573884, 31544778, 29606556). A functional study with limited validation assaying the biophysical properties of mutant rat skeletal muscle cells that were expressed in HEK293T cells is supportive of a damaging effect on protein function suggestive of a loss-of-function mechanism (PMID: 8740371). Computational evidence predicts a deleterious effect for the missense substitution (REVEL = 0.871) and predicts no impact on splicing (SpliceAI) for the nucleotide change. Other missense in this codon have been reported as pathogenic for SCN4A-related skeletal muscle sodium channelopathies (ClinVar ID: 5903, 5920). Based on the classification scheme RMH Modified ACMG/AMP Guidelines v1.7.0, this variant is classified as PATHOGENIC. Following criteria are met: PS4, PP1_Strong, PM2_Supporting, PP3, PS3_Supporting. -

Hyperkalemic periodic paralysis

Pathogenic:1

Jan 13, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 1306 of the SCN4A protein (p.Gly1306Ala). This variant is present in population databases (rs80338792, gnomAD 0.0009%). This missense change has been observed in individual(s) with myotonia fluctuans (PMID: 7980103, 8308722, 26080010, 26885337). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 5908). 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) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on SCN4A protein function. Experimental studies have shown that this missense change affects SCN4A function (PMID: 7473241, 16392038). This variant disrupts the p.Gly1306 amino acid residue in SCN4A. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 8308722, 16832098, 17823953, 20713951). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Myotonia fluctuans

Pathogenic:1

Nov 01, 1994

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Potassium-aggravated myotonia

Pathogenic:1

Jun 22, 2022

MGZ Medical Genetics Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Paramyotonia congenita of Von Eulenburg;C0238357:Hyperkalemic periodic paralysis;C2750061:Hypokalemic periodic paralysis, type 2;C2931826:Potassium-aggravated myotonia

Other:1

GenomeConnect - Invitae Patient Insights Network

Significance: not provided

Review Status: no classification provided

Collection Method: phenotyping only

Variant interpreted as Pathogenic and reported on 12-18-2017 by Invitae. GenomeConnect-Invitae Patient Insights Network assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. Registry team members make no attempt to reinterpret the clinical significance of the variant. Phenotypic details are available under supporting information. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.32

BayesDel_addAF

Pathogenic

0.42

BayesDel_noAF

Pathogenic

0.36

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.81

Eigen

Uncertain

0.43

Eigen_PC

Uncertain

0.38

FATHMM_MKL

Uncertain

0.91

LIST_S2

Uncertain

0.97

M_CAP

Pathogenic

0.79

MetaRNN

Pathogenic

0.90

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.0

PrimateAI

Pathogenic

0.84

PROVEAN

Pathogenic

-4.5

REVEL

Pathogenic

0.87

Sift

Uncertain

0.0010

Sift4G

Uncertain

0.012

Polyphen

0.54

Vest4

0.56

MutPred

0.79

Gain of catalytic residue at G1306 (P = 0.0465);

MVP

0.85

MPC

0.46

ClinPred

0.98

GERP RS

3.4

Varity_R

0.70

gMVP

0.44

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over