Paroxysmal nonkinesigenic dyskinesia during wakefulness and sleep associated with familial febrile convulsions

Objective Paroxysmal dyskinesias (PD) are currently classified in: paroxysmal kinesigenic and nonkinesigenic dyskinesia (PNKD), paroxysmal exertioninduced dyskinesia and paroxysmal hypnogenic dyskinesia. Recent studies described four families with benign infantile convulsions and paroxysmal dyskinesia inherited together as an autosomal dominant trait linked to chromosome 16 (ICCA syndrome). Methods and results Two men (aged 30 and 20 years) with a family history of febrile convulsions have presented attacks of paroxysmal nonkinesigenic dyskinesia since 15 months of age, characterized by choreic and bailie movements with dystonic components of limbs and trunk lasting 3-5 minutes. Attacks occur at rest, many times a day, during wakefulness and non-REM sleep and are not provoked by movements or exercise. We excluded the commonest causes of secondary dyskinesia. Video-polygraphic recordings of attacks do not show paroxysmal EEG activity. Conclusions Our cases present a non-familial idiopathic paroxysmal nonkinesigenic dyskinesia associated with familial febrile convulsions. They differ from the classical form of PNKD because attacks also occur during sleep and from ICCA syndrome because familiarity is for febrile convulsions and not benign infantile nonfebrile convulsions. This confirms the clinical heterogeneity of PD. Further cases are needed to establish whether the association with febrile convulsions is casual or may represent a phenotypic variant of the ICCA syndrome.