Number | 23 | 4 | 2 (siblings) | 4 |
Female:Male | 16:7 (2.3:1) | 1:3 | 1:1 | 1:3 |
Mean age (years) at onset (SD), range | 4.5 (4.6), 1 to 15 | 7.3 (3.9), 5 to 13 | 0.3 (0.3), 0.1 to 0.5 | 37.0 (8.2), 30 to 48 |
Mean duration (years) of follow-up (SD) | 37.7 (17.9) | 59.5 (13.4) | 23.0 (7.1) | 19.8 (12.9) |
Initial symptoms | Onset with walking difficulties | Onset with episodic foot dystonia, toe walking or progressive scoliosis | Hypotonia in the first year of life | Onset with dystonic and/or resting tremor or mild atremulous parkinsonism |
Disease course (prior to treatment) | Slowly progressive dystonia, generalising/increasing in severity over the next 10 to 20 years, subsequently development of dystonic tremor and mild parkinsonism, diurnal fluctuation | Very mild symptoms throughout disease | Followed by severe delay in motor development, and rapid progression of severe generalised dystonia and pronounced involvement of the oropharyngeal region | Symptoms remaining mild |
Treatment | Excellent response to levodopa | No therapy needed | Resolving symptoms with levodopa in one, only partial improvement in the other sibling | Treatment required due to tremor only in 50%, excellent response to levodopa |