Mini-review: multiple developmental forms of parkinsonism. The basis for further research as to the pathogenesis of parkinsonism.

A range of extrapyramidal disturbances have been reported in children following early brain damage. In adults, damage to the basal ganglia can elicit abnormal motor activity in either direction; it would seem reasonable that the same would apply to damage occurring at an earlier developmental stage. The Viennese paediatrician Widhalm described a hypokinetic/parkinsonoid syndrome ("infantile hypokinetic-hypertonic syndrome with Parkinson symptomatic") presented by a significant minority of the children with extrapyramidal movement disturbances, corresponding to the mild rigid-akinetic type of Parkinson's disease. In contrast to classical parkinsonism, but consistent with some forms of post-encephalitic parkinsonism, the syndrome was reversible, although only after L-DOPA therapy. Widhalm's observation that at least one form of childhood parkinsonism can be cured with L-DOPA also suggests that the amino acid plays a more active role than mere replacement therapy in children, perhaps also acting as a neurotrophic agent. It is proposed that environmental factors, including viral and risk factors associated with pregnancy and birth, together with genetically determined lability, may increase the incidence of early hypokinesia/parkinsonism in particular and of Parkinson's disease in later life by disturbing the immature basal ganglia at critical developmental stages. The spectrum disorder of Parkinson's disease thereby occurs as a number of various etiopathologically distinct syndrome subtypes, including early onset developmental forms caused by in utero or early post partum trauma.