[Autosomal recessive juvenile parkinsonism: its pathogenesis is involved in the ubiquitin-proteasome pathway]

The contribution of genetic factors in the pathogenesis of PD is supported by the demonstration of the high concordance in twins studies using PET, the increased risk among relatives of PD patients in case control and family studies, and the existence of familial PD and parkinsonism by single gene defect. Recently, two genes such as alpha-synuclein and parkin have been identified. alpha-Synuclein is involved in a rare dominant form of familial PD with dopa responsive parkinsonian features and Lewy body positive pathology. In contrast, parkin is responsible for autosomal recessive form (AR-JP) of early onset PD with Lewy body-negative pathology. To date, variable mutations such as deletions or point mutations have been reported in AR-JP patients from world wide. In addition, the localization of parkin indicates parkin may are involved in the axonal transport system. More recently, we have found that parkin interacts with ubiquitin-conjugating enzyme, UbcH 7, and is functionally linked to the ubiquitin-proteasome pathway as a ubiquitin ligase. These findings fit the characteristics of lack of Lewy bodies which are cytoplasmic inclusions considered a pathological hallmark. Our findings should enhance the exploration of the mechanisms of neuronal death in PD as well as other neurodegenerative disorders of which variable inclusion bodies are observed.