[Segawa's disease: progressive dystonia responsive to L-dopa. A case report].

Segawa's disease (SD) is a hereditary progressive dystonia with marked diurnal fluctuation with onset in childhood or adolescence and a striking responsiveness to L-dopa. Here we describe a typical case of SD in a 28 year old woman whose disease begun at the age of 18 years. This patient had a second cousin with probable hereditary spastic paraplegia (Strumpell's familiar spastic paraplegia) who had no benefit on a recent L-dopa trial. Due to this family history our patient had been misdiagnosed as Strumpell's disease for more than 10 years. There was no other apparent case of SD in the family. Her father had an atypical gait but was otherwise normal. Her daughter had motor developmental delay due to hypotonia. Pes cavus was a common feature to the patient, her father and her cousin.