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Gene

SCN4A

sodium voltage-gated channel alpha subunit 4

Summary

Cytogenetic location
17q23.3
Coordinates
Chromosome 17: 63,938,554–63,972,918 (GRCh38)
Exons
24 exons across 34.4 kb
Protein
1,836 amino acids
Inheritance
Autosomal dominant
Also known as
Nav1.4, HYPP, SkM1
Previous symbols
HYKPP
MANE Select transcript
ENST00000435607.3NM_000334.4
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

Reference genomeGRCh38

Positions on gene and variant pages follow this choice, in this browser.

Curated reports relevant to this gene

  • Congenital Myasthenic Syndrome

    • Congenital Myasthenic Syndrome (All Types)

      Umbrella term covering all congenital myasthenic syndromes, including the common CHRNE, RAPSN, DOK7 and MUSK forms.

      • 2 GenCC submitters rate it definitive or strong
      What knowing changes

      Many forms respond to specific medications such as pyridostigmine, salbutamol or ephedrine, and the right choice depends on the gene involved.

  • Dystonia, Myotonia, Paroxysmal Dyskinesia

    • Paramyotonia CongenitaAutosomal dominant

      A skeletal-muscle sodium channel (SCN4A) disorder causing muscle stiffness that worsens with cold and repeated activity, sometimes followed by weakness.

      • 4 GenCC submitters rate it definitive or strong
    • Potassium-Aggravated MyotoniaAutosomal dominant

      An SCN4A-related myotonia in which muscle stiffness is made worse by potassium, including myotonia fluctuans and myotonia permanens.

      • 1 GenCC submitter rates it definitive or strong

  • Familial Periodic Paralysis

    • Periodic ParalysisAutosomal dominant

      Editor note: classified as genetic in ORDO but we treat as neutral here

      • 3 GenCC submitters rate it definitive or strong

Inheritance

Autosomal dominant
One changed copy, from either parent, is enough. A parent who has one passes it on to each child with a one-in-two chance.

How SCN4A is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
Chromosome 17, with a bracket where SCN4A sits. SCN4A and 28 genes near it on chromosome 17, from 63,455,736 to 64,455,735.Chromosome 1717q23.3p13.3p13.2p13.1p12p11.2p11.1q11.1q11.2q12q21.1q21.2q21.31q21.32q21.33q22q23.1q23.2q23.3q24.1q24.2q24.3q25.1q25.2q25.363.6 Mb63.8 Mb64 Mb64.2 Mb64.4 MbACE: 63,477,058–63,498,380, forward strandACE: 63,484,823–63,521,848, forward strandKCNH6: 63,523,310–63,548,987, forward strandKCNH6DCAF7: 63,550,222–63,594,286, forward strandDCAF7: 63,550,603–63,608,347, forward strandTACO1: 63,600,879–63,612,023, forward strandTACO1MAP3K3: 63,622,379–63,696,310, forward strandMAP3K3STRADA: 63,682,336–63,742,005, reverse strandSTRADALIMD2: 63,695,883–63,701,183, reverse strandLIMD2: 63,702,845–63,752,097, reverse strandCCDC47: 63,745,250–63,776,351, reverse strandCCDC47DDX42: 63,773,603–63,820,451, forward strandDDX42FTSJ3: 63,819,113–63,830,012, reverse strandFTSJ3PSMC5: 63,827,082–63,832,244, forward strandPSMC5SMARCD2: 63,832,078–63,843,065, reverse strandSMARCD2CSH2: 63,872,007–63,873,769, reverse strandCSH2GH2: 63,880,205–63,881,970, reverse strandGH2CSH1: 63,894,906–63,896,667, reverse strandCSHL1: 63,909,596–63,911,348, reverse strandGH1: 63,917,200–63,918,839, reverse strandGH1: 63,917,203–63,931,385, reverse strandCD79B: 63,928,738–63,932,629, reverse strandCD79BSCN4A: 63,938,554–63,972,918, reverse strandSCN4APRR29: 63,998,344–64,004,305, forward strandPRR29ICAM2: 64,002,594–64,020,640, reverse strandICAM2ERN1: 64,039,080–64,130,819, reverse strandERN1TEX2: 64,147,227–64,263,293, reverse strandTEX2PECAM1: 64,319,415–64,431,594, reverse strandPECAM1MILR1: 64,449,037–64,492,770, forward strandMILR1Diagram of SCN4A: 24 exons on the reverse strand of chromosome 17Exon 24: 32 known disease-causing sitesExon 23: 6 known disease-causing sitesExon 22: 5 known disease-causing sitesExon 21: 3 known disease-causing sitesExon 20: 2 known disease-causing sitesExon 19: 9 known disease-causing sitesExon 18: 7 known disease-causing sitesExon 17: 2 known disease-causing sitesExon 15: 2 known disease-causing sitesExon 14: 5 known disease-causing sitesExon 13: 9 known disease-causing sitesExon 12: 8 known disease-causing sitesExon 11: 4 known disease-causing sitesExon 10: 1 known disease-causing siteExon 9: 6 known disease-causing sitesExon 8: 4 known disease-causing sitesExon 7: 2 known disease-causing sitesExon 6: 7 known disease-causing sitesExon 5: 4 known disease-causing sitesExon 4: 3 known disease-causing sitesExon 3: 1 known disease-causing siteExon 1: 2 known disease-causing sitesExon 24: 63,938,554–63,941,993, 3,440 basesExon 23: 63,942,826–63,943,096, 271 basesExon 22: 63,943,746–63,943,850, 105 basesExon 21: 63,944,673–63,944,810, 138 basesExon 20: 63,945,007–63,945,060, 54 basesExon 19: 63,945,360–63,945,638, 279 basesExon 18: 63,947,045–63,947,167, 123 basesExon 17: 63,947,890–63,948,063, 174 basesExon 16: 63,948,611–63,948,765, 155 basesExon 15: 63,949,393–63,949,528, 136 basesExon 14: 63,951,424–63,951,900, 477 basesExon 13: 63,957,162–63,957,518, 357 basesExon 12: 63,959,265–63,959,438, 174 basesExon 11: 63,961,193–63,961,431, 239 basesExon 10: 63,963,672–63,963,825, 154 basesExon 9: 63,964,468–63,964,677, 210 basesExon 8: 63,966,102–63,966,243, 142 basesExon 7: 63,966,481–63,966,544, 64 basesExon 6: 63,968,023–63,968,355, 333 basesExon 5: 63,971,162–63,971,253, 92 basesExon 4: 63,971,722–63,971,850, 129 basesExon 3: 63,972,136–63,972,225, 90 basesExon 2: 63,972,352–63,972,470, 119 basesExon 1: 63,972,569–63,972,918, 350 bases24201510515′3′

Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

Nearby genes from Ensembl release 116, on GRCh38.

Exons make up 7.8 kb of the gene's 34.4 kb; 5,511 of those bases code for the protein.

How a genome test reads SCN4A

131

positions in SCN4A where ClinVar classes a change as pathogenic or likely pathogenic

None of them falls in a region short reads find hard.

A whole genome covers all 34.4 kb of SCN4A, introns included, not only the 7.8 kb of exons.

Where this comes from

  • HGNC: the gene's symbol, name, other symbols and location.
  • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
  • GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
  • The ACMG secondary findings list, SF v3.2.
  • ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
  • Data release 2026.10.16-c6eea6bf.

Cite this page

APA

Dante Labs. (n.d.). SCN4A gene: sodium voltage-gated channel alpha subunit 4. Retrieved 17 October 2026, from https://dantelabs.com/genes/scn4a

Vancouver

Dante Labs. SCN4A gene: sodium voltage-gated channel alpha subunit 4 [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/scn4a

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