Parkinson Disease 21, also known as park21, is related to atypical juvenile parkinsonism and tremor, hereditary essential, 3. An important gene associated with Parkinson Disease 21 is PARK21 (Parkinson Disease 21), and among its related pathways/superpathways is Parkinson's disease pathway. Affiliated tissues include brain and subthalamic nucleus, and related phenotypes are tremor and rigidity