A rare parkinsonian disorder with characteristics of unilateral body atrophy and slowly progressive, ipsilateral hemiparkinsonian signs (bradykinesia, rigidity, and tremor). Patients typically present with unilateral, action-induced dystonia, in upper or lower limbs, that progresses and becomes bilateral or with tremor which occurs predominantly at rest and progresses to hemiparkinsonism. Scoliosis, scapular winging, raised shoulders, brisk reflexes and extensor plantars are frequently associated.