Dopa-Responsive Dystonia, GTP Cyclohydrolase Deficiency

Dopa-responsive dystonia due to GTP cyclohydrolase deficiency typically presents in childhood with limb dystonia, gait disturbance, and diurnal fluctuation of symptoms that respond dramatically to low-dose levodopa. Some individuals may also have parkinsonism or other neurologic signs. Genetic testing confirms the diagnosis and supports treatment planning and counseling.