[Hereditary progressive dystonia with marked diurnal fluctuation--clinical features and GTP cyclohydrolase I gene mutations].

Hereditary progressive dystonia with marked diurnal fluctuation (HPD) is a disorder characterized by childhood-onset dystonia and a dramatic and sustained response to low doses of levodopa. Recently the GTP cyclohydrolase I(GCH-I) gene was isolated as the first causative gene for HPD. We analyzed the GCH-I gene in 8 clinically diagnosed HPD patients and found different point mutations in GCH-I gene in 3 subjects. The clinical features of these patients considerably resembled each other. Our results imply that although clinically diagnosed HPD subjects could present diverse symptoms, patients with a mutant GCH-I gene might share homogeneous clinical manifestations.