Infantile hypotonia and paroxysmal dystonia: a variant of alternating hemiplegia of childhood?

We report 2 children with early onset of hypotonia and frequent episodes of paroxysmal dystonia. The episodes were abolished even by brief naps. One of the children developed alternating hemiplegia in the second decade. These children seem to have a variant of the now well-recognized syndrome of alternating hemiplegia of childhood. In that disorder, episodes of alternating hemiplegia develop before the age of 18 months. This syndrome must be considered in the differential diagnosis of paroxysmal dystonia in childhood.