Neuronal intranuclear inclusion disease is a rare, neurodegenerative disorder with onset in childhood. We report a single case natural history over 10 years and present a review of juvenile parkinsonism and neuronal intranuclear inclusion disease. Our patient was initially seen at the University of Rochester at age 12 years after 4 years of progressive dysarthria, dysphagia, and clumsiness. His neurologic examination was notable for parkinsonism. He had excellent initial response to levodopa, but subsequently developed dopa-induced motor fluctuations, dyskinesias, psychosis, and dystonia. Later in the course, he developed multiple nonmotor symptoms and ultimately died from respiratory failure. Neuropathology demonstrated large eosinophilic nuclear inclusions and small ubiquitin-related modifier 1 (SUMO-1) immunoreactivity, confirming the diagnosis of neuronal intranuclear inclusion disease. This diagnosis should be considered in a patient presenting with juvenile parkinsonism. Clues to the diagnosis include early-onset dopa-induced dyskinesias, gastrointestinal dysfunction, and oculogyric crises.
Keywords: SUMO-1; dystonia; juvenile parkinsonism; neurodegeneration.