SCN4A-related non-dystrophic myotonia: genes and variants
SCN4A-related non-dystrophic myotonia is linked to 1 analyzed protein (SCN4A). 3 DNA variants are known to cause it; 3 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to SCN4A-related non-dystrophic myotonia
SCN4A: Sodium channel protein type 4 subunit alpha
Its rapid sodium current initiates and propagates skeletal-muscle action potentials. Gain- and loss-of-function variants cause disorders of muscle excitability including sodium-channel myotonia, paramyotonia congenita, periodic paralysis, and some congenital myopathies.
3 disease-causing and 3 uncertain variants in SCN4A are linked to SCN4A-related non-dystrophic myotonia.
Known disease-causing variants in SCN4A-related non-dystrophic myotonia
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| SCN4A I1157N | 1157 | III | Disease-causing |
| SCN4A V1166A | 1166 | III | Disease-causing |
| SCN4A L1433R | 1433 | IV | Disease-causing |
Same protein, different disease
- Hyperkalemic periodic paralysis is also caused by SCN4A variants; they fall mostly in different places as the SCN4A-related non-dystrophic myotonia variants (62 disease-causing).
- Paramyotonia congenita of Von Eulenburg is also caused by SCN4A variants; they fall mostly in different places as the SCN4A-related non-dystrophic myotonia variants (15 disease-causing).
- Potassium-aggravated myotonia is also caused by SCN4A variants; they fall mostly in different places as the SCN4A-related non-dystrophic myotonia variants (14 disease-causing).
- Hypokalemic periodic paralysis is also caused by SCN4A variants; they fall mostly in different places as the SCN4A-related non-dystrophic myotonia variants (11 disease-causing).
- Congenital myopathy 22A, classic is also caused by SCN4A variants; they fall mostly in different places as the SCN4A-related non-dystrophic myotonia variants (8 disease-causing).
Diseases related to SCN4A-related non-dystrophic myotonia
- Amyotrophic lateral sclerosis, also linked to SCN4A
- Cardiac arrhythmia, also linked to SCN4A
- Sotos syndrome, also linked to SCN4A
- Hyperkalemic periodic paralysis, also linked to SCN4A
- Hypokalemic periodic paralysis, also linked to SCN4A
- Congenital myasthenic syndrome 17, also linked to SCN4A
- Skeletal muscle channelopathy, also linked to SCN4A
- Epilepsy, also linked to SCN4A
- Paramyotonia congenita of Von Eulenburg, also linked to SCN4A
- Potassium-aggravated myotonia, also linked to SCN4A
- Congenital myopathy 22A, classic, also linked to SCN4A
- Fetal akinesia deformation sequence, also linked to SCN4A
Frequently asked questions
Which genes are linked to SCN4A-related non-dystrophic myotonia?
In CATVariant, SCN4A-related non-dystrophic myotonia is linked to 1 analyzed protein: SCN4A (Sodium channel protein type 4 subunit alpha).
How many genetic variants are linked to SCN4A-related non-dystrophic myotonia?
6 variants: 3 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 3 are of uncertain significance or have conflicting reports.
Which uncertain variants in SCN4A-related non-dystrophic myotonia look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
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