Persistence of Facio‐Skeletal Myorhythmia During Sleep in anti‐IgLON5 Disease

Myorhythmia is a hyperkinetic movement disorder characterized by slow, repetitive, rhythmic, cranial and limb contractions, typically disappearing during sleep. Infectious, autoimmune or vascular lesions involving brainstem or diencephalic structures are the most common etiologies.1 Anti-IgLON5 disease was originally reported as a progressive neurological syndrome characterized by a preeminent sleep disorder, variably associated with bulbar dysfunctions, gait instability, oculomotor abnormalities and cognitive decline.2, 3 Since initial descriptions, several hyperkinetic movement disorders have been described, including oro-facial myorhythmia in few cases.4, 5 We describe a case of anti-IgLON5 disease-related myorhythmia involving both facial and limb muscles, persisting during physiological and pathological sleep.