NM_000334.4:c.1018G>A

Variant names:

• chr17-63968041-C-T
• rs147936148
• NM_000334.4:c.1018G>A

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BP6 BS1

The NM_000334.4(SCN4A):​c.1018G>A​(p.Ala340Thr) variant causes a missense change. The variant allele was found at a frequency of 0.000104 in 1,613,834 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00014 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00010 (0 hom.)
• Consequence: SCN4A NM_000334.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:5
• Conservation: PhyloP100: 3.60

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 Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.018307596).
• BP6: Variant 17-63968041-C-T is Benign according to our data. Variant chr17-63968041-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 429845.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Benign=4, Uncertain_significance=4}.
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.000138 (21/152198) while in subpopulation EAS AF= 0.00347 (18/5182). AF 95% confidence interval is 0.00224. There are 0 homozygotes in gnomad4. There are 11 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN4A	NM_000334.4	c.1018G>A	p.Ala340Thr	missense_variant	Exon 6 of 24	ENST00000435607.3	NP_000325.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN4A	ENST00000435607.3	c.1018G>A	p.Ala340Thr	missense_variant	Exon 6 of 24	1	NM_000334.4	ENSP00000396320.1

Frequencies

GnomAD3 genomes AF: 0.000138 AC: 21 AN: 152086 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00347

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.000480

GnomAD3 exomes AF: 0.000193 AC: 48 AN: 248490 Hom.: 0 AF XY: 0.000163 AC XY: 22 AN XY: 134882

Gnomad AFR exome AF: 0.0000646

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00217

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000623

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000101 AC: 147 AN: 1461636 Hom.: 0 Cov.: 32 AF XY: 0.000113 AC XY: 82 AN XY: 727094

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00209

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000522

Gnomad4 OTH exome AF: 0.0000663

GnomAD4 genome AF: 0.000138 AC: 21 AN: 152198 Hom.: 0 Cov.: 32 AF XY: 0.000148 AC XY: 11 AN XY: 74414

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00347

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.000475

Alfa AF: 0.000106 Hom.: 0

Bravo AF: 0.000151

ExAC AF: 0.000165 AC: 20

Asia WGS AF: 0.000866 AC: 3 AN: 3478

EpiCase AF: 0.000164

EpiControl AF: 0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5 Benign:5

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

May 09, 2019

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 21, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis indicates that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Hyperkalemic periodic paralysis Benign:2

Dec 09, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 13, 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. -

Microcephaly Uncertain:1

-

Department of Pediatrics, Samsung Medical Center, Samsung Medical Center

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: research

- -

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

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Congenital myasthenic syndrome 16 Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Hypokalemic periodic paralysis, type 2 Benign:1

Jan 13, 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. -

Paramyotonia congenita of Von Eulenburg Benign:1

Jan 13, 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. -

Potassium-aggravated myotonia Benign:1

Jan 13, 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.086
BayesDel_addAF	Benign	-0.27	T
BayesDel_noAF	Benign	-0.16
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.67	D
Eigen	Benign	-0.066
Eigen_PC	Benign	-0.00056
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	D
M_CAP	Uncertain	0.14	D
MetaRNN	Benign	0.018	T
MetaSVM	Uncertain	0.73	D
MutationAssessor	Benign	1.5	L
PrimateAI	Benign	0.47	T
PROVEAN	Benign	-1.1	N
REVEL	Uncertain	0.34
Sift	Benign	0.33	T
Sift4G	Benign	0.33	T
Polyphen		0.30	B
Vest4		0.17
MVP		0.81
MPC		0.37
ClinPred		0.030	T
GERP RS		4.1
Varity_R		0.13
gMVP		0.70

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: rs147936148; hg19: chr17-62045401;