Idiopathic fluctuating dystonia: a case of foot dystonia and writer's cramp responsive to L-dopa.

A forme fruste of progressive idiopathic dystonia is reported in a girl, starting at eight years and followed to 24 years of age. The first symptom was isolated dystonia of the left foot and later writer's cramp developed in the hands. Fluctuations of the dystonia occurred later in the course of the disorder, which were not related to the sleep-walking cycle. Complete remission of symptoms was obtained with low dosage of L-dopa. This case broadens the spectrum of fluctuating dopa-sensitive progressive childhood dystonias and provides evidence for writer's cramp being a form of focal dystonia.