RecruitingNot applicableNCT07194174
Neuromuscular
Periodic Paralysis
Also known as hyperkalemic periodic paralysis, hypokalemic periodic paralysis, HypoPP, HyperPP
Periodic Paralysis encompasses a group of channelopathies causing episodic attacks of muscle weakness or paralysis associated with abnormal serum potassium levels. Hypokalemic Periodic Paralysis (HypoPP) is caused by mutations in CACNA1S or
ORPHA:681 ↗Gene SCN4AGene CACNA1SPrevalence 1 in 100,000Onset Childhood to adolescence (first decade for HyperPP, second for HypoPP)Autosomal dominant
1
studies recruiting now
as of 7 Sept 2026
12
studies registered in total
as of 7 Sept 2026
1
countries with a recruiting site
as of 7 Sept 2026
26 Sept 2025
most recent study posted
among recruiting studies
Recruiting trials
Showing the 1 most recently updated recruiting study, as recorded 7 Sept 2026. Live status on each study page.
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About Periodic Paralysis
Periodic Paralysis encompasses a group of channelopathies causing episodic attacks of muscle weakness or paralysis associated with abnormal serum potassium levels. Hypokalemic Periodic Paralysis (HypoPP) is caused by mutations in CACNA1S or SCN4A and is triggered by high carbohydrate intake or rest after exercise; Hyperkalemic Periodic Paralysis (HyperPP) is caused by SCN4A gain-of-function variants and is triggered by fasting, cold, or potassium ingestion. Persistent interictal weakness develops in many patients over time.
Common clinical features
Episodic attacks of flaccid muscle weakness or paralysis lasting hoursAttacks triggered by identifiable precipitants (food, exercise, cold, stress)Normal or near-normal strength between attacks early in diseaseProgressive interictal proximal muscle weakness in chronic diseaseMyotonia (in HyperPP with SCN4A mutations)Respiratory involvement during severe attacksAbnormal serum potassium during attacks (low in HypoPP, high in HyperPP)
From Orphanet’s phenotype annotations (CC BY 4.0). Not a complete list.
Before you apply
Things trial teams commonly ask about for Periodic Paralysis. Not eligibility rules; those are set by each study.
- Genetic subtype (HypoPP vs HyperPP and the causative gene) is required for most trials — potassium channel subtype (CACNA1S vs SCN4A) determines drug mechanism eligibility
- Attack diary documentation including frequency, duration, potassium levels during attacks, and known triggers is essential and may form part of a run-in period in trial protocols
- Exercise EMG (McManis protocol) and provocative testing results may be requested as objective diagnostic confirmation alongside genetic testing
Related conditions
Information, not medical advice. Trial listings are shown as recorded on ClinicalTrials.gov; whether any study is right for you is a decision for you and your clinicians, and eligibility is decided by each research team. Disease information from Orphanet (CC BY 4.0).