[Hereditary parkinsonism-dystonia syndrome of juvenile onset with diurnal fluctuations]

Abstract

Symptoms of fluctuating dystonia developed in 4 subjects of the same family during childhood or adolescence. In the 2 sisters, these symptoms were initially or subsequently associated with signs of parkinsonism, whereas in the 2 brothers they disappeared, spontaneously in at least 1 case, and signs of parkinsonism appeared later after a free interval. Anticholinergic agents and L-Dopa proved very effective against all extrapyramidal signs. These cases are similar to those gathered by Nygaard et al. in 1988 under the term "Dopa-responsive dystonia". Yet laboratory data seem to confirm that the common physiological mechanism is a disorder of tetrahydrobiopterin metabolism. Serum and urinary biopterin levels were lowered in our 4 cases but were normal in an unaffected sister. However, like the subjects affected this third sister showed a decrease of platelet serotonin which was taken as being a consequence of aromatic aminoacid hydroxylation defect due to tetrahydrobiopterin deficiency.