Autosomal recessive juvenile parkinsonism

Autosomal recessive juvenile parkinsonism (AR-JP) is a hereditary neurodegenerative disorder characterized by levodopa-responsive parkinsonism with onset before age 40 years and a slowly progressive course. Families with this condition have been described predominantly in Japanese population, occasionally under different names including an autosomal recessive early-onset parkinsonism with diurnal fluctuation (AR-EPDF) or a familial form of juvenile parkinsonism. Recently, the causative gene for AR-JP was mapped on chromosome 6q25.2-q27, and subsequently a novel gene 'parkin' was identified by means of positional cloning. In this manuscript, we review the clinical, pathological and genetical aspects of AR-JP. It would not only promise to provide important insights into the molecular mechanisms of selective degeneration of dopaminergic neurons in AR-JP, but also bring insights into the mechanisms of degeneration of these neurons in Parkinson's disease.