NM_000334.4:c.1328T>C

Variant names:

• chr17-63964592-A-G
• rs1555604153
• NM_000334.4:c.1328T>C
• SCN4A p.Leu443Pro

GermlineCancer (beta)

Variant summary

Our verdict is Likely pathogenic.

+9 Likely Pathogenic

-7

-6

-1

0

+5

+6

+9

+10

BenignB

Likely BenignLB

UncertainVUS

Likely PathogenicLP

PathogenicP

The variant received 9 classification points (ACMG Germline Pathogenicity v2019). PM1PM2PP3_StrongPP5

The NM_000334.4(SCN4A):c.1328T>C (p.Leu443Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant is absent from the gnomAD population database at sites with sufficient sequencing coverage. In-silico predictor (REVEL) classifies this variant as likely damaging/oncogenic. Splicing prediction tools (SpliceAI) predict no significant impact on normal splicing. The affected nucleotide is highly conserved across species (PhyloP 100-way vertebrate score: 9.32). Variant has been reported in ClinVar as Pathogenic/Likely Pathogenic (no review stars). Other variants at the same amino acid position have been reported in ClinVar (not pathogenic): p.L443= (synonymous): Likely_benign (ClinVar VariationId 4701996, 1 star)

• Frequency: Genomes: not found (cov: 33)
• Consequence: SCN4A NM_000334.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 9.32
• Publications: 0 publications found

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: Labcorp Genetics (formerly Invitae), Orphanet, G2P, Genomics England PanelApp
• hypokalemic periodic paralysis, type 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
• paramyotonia congenita of Von Eulenburg

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, Laboratory for Molecular Medicine
• SCN4A-related myopathy, autosomal recessive

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, ClinGen, Illumina
• potassium-aggravated myotonia

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• congenital myasthenic syndrome 16

  Inheritance: AR Classification: STRONG, LIMITED Submitted by: 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

LOC105371858 (HGNC:):

Classification according to ACMG Germline Pathogenicity v2019

Our verdict: Likely_pathogenic. The variant received 9 points.

• PM1: Missense neighbourhood hotspot (≥2 P/LP within ±8 AA, OR ≥ 5 vs. background) — PM1; In-domain: 3 pathogenic, 1 benign rare missense variants (OR vs. background: 11.7).; ±8 AA neighbourhood: 5 pathogenic, 0 benign (OR vs. background: 55.0).
• PM2: Absent from gnomAD (AD/XL gene) — PM2; Absent from gnomAD at well-covered site (MOI: AD+AR) (base 0.0001, raised to 0.0005 by highest known P/LP ClinVar AF 0.000524) — PM2 moderate.
• PP3: Germline meta computational scorer (REVEL/MetaRNN/BayesDel) predicts damaging effect — strong evidence (PP3); Splicing verdict: not pathogenic.; Germline computational verdict: pathogenic (Strong).
• PP5: ClinVar 0-star pathogenic — supporting (PP5); ClinVar germline classification: Pathogenic/Likely Pathogenic, 0 star(s).

Variant Effect in Transcripts

Automated classification analysis was done for transcript: NM_000334.4. You can select a different transcript below to see updated classification assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN4A	NM_000334.4	MANE Select	c.1328T>C	p.Leu443Pro	missense	Exon 9 of 24	NP_000325.4	P35499

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN4A	ENST00000435607.3	TSL:1 MANE Select	c.1328T>C	p.Leu443Pro	missense	Exon 9 of 24	ENSP00000396320.1	P35499

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	-	Hyperkalemic periodic paralysis (1)
-	1	-	Neuromuscular disease (1)
1	-	-	SCN4A-related myopathy, autosomal recessive (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.1	H
PhyloP100		9.3
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-5.7	D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Varity_R		0.97
gMVP		0.99

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs1555604153;

hg19: chr17-62041952;

ACMG debug oncogenicity

ACGS debug oncogenicity

ACMG debug germline

Submit to ClinVar