Clinical and neuropathological aspects of autosomal recessive juvenile parkinsonism.

The onset of autosomal recessive-type parkinsonism is usually at a relatively young age (i.e. before the age of 40 years) and is thus called autosomal recessive juvenile parkinsonism (AR-JP). Here the clinical features, laboratory and imaging findings, neuropathological features, differential diagnosis and treatment options of AR-JP are described. We have treated 17 patients with AR-JP; they presented with sleep benefit in parkinsonian symptoms and foot dystonia as specific signs. The parkinsonian triad was mild, and the tremor was usually fine postural. A postural instability and adiadochokinesia were rather prominent. Gait freezing and hyperreflexia were frequently observed. The levodopa efficacy was sufficient and the clinical course was benign; however, choreic limb dyskinesia and the wearing-off phenomenon occurred easily. A neuropathological examination of one of the patients revealed that in the substantia nigra pars compacta and locus ceruleus, the number of neurons was low, and the content of neuromelanin in the neurons was small. There were focal degenerations (e.g. gliosis and extraneuronal free melanin) in the substantia nigra pars compacta. In addition, Lewy bodies were not found anywhere in the central nervous system. Considering these specific clinical and neuropathological findings, AR-JP seems to constitute one disease entity.