Isaac syndrome
MONDO:0019399Mondo
Findings
No curated finding names Isaac syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Isaac's syndrome is an immune-mediated peripheral motor neuron disorder characterized by continuous muscle fiber activity at rest resulting in muscle stiffness, cramps, myokymia, and pseudomyotonia.
Definition from the Mondo Disease Ontology (MONDO:0019399), read 2026-09-29. CC BY 4.0.
Features
13 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Anti-CASPR2HPOHP:5000005
- Frequent (30% to 79% of cases)
- Calf muscle hypertrophyHPOHP:0008981
- Frequent (30% to 79% of cases)
- EEG abnormalityHPOHP:0002353
- Frequent (30% to 79% of cases)
- EMG: myokymic dischargesHPOHP:0100288
- Frequent (30% to 79% of cases)
- FasciculationsHPOHP:0002380
- Frequent (30% to 79% of cases)
- HyperhidrosisHPOHP:0000975
- Frequent (30% to 79% of cases)
- Muscle fibrillationHPOHP:0010546
- Frequent (30% to 79% of cases)
- Muscle spasmHPOHP:0003394
- Frequent (30% to 79% of cases)
- Muscle stiffnessHPOHP:0003552
- Frequent (30% to 79% of cases)
- MyokymiaHPOHP:0002411
- Frequent (30% to 79% of cases)
- Weight lossHPOHP:0001824
- Frequent (30% to 79% of cases)
- Distal sensory impairmentHPOHP:0002936
- Occasional (5% to 29% of cases)
Show the remaining 1
- Muscle weaknessHPOHP:0001324
- Very rare (1% to 4% of cases)
Where it sits
- A kind of
Other names
7 names
Resolves to: Isaac syndrome
- Also called
- acquired neuromyotoniacontinuous muscle fiber activity syndromecontinuous muscle fibre activity syndromeIsaacs' syndromeneuromyotoniaperipheral nerve hyperexcitabilityQuantal squander syndrome