Neuronal Intranuclear Inclusion Disease: Longitudinal Case Report of Motor and Nonmotor Symptoms

Area of Science:

• Neurology
• Neurodegenerative Diseases
• Pediatric Neurology

Background:

• Neuronal intranuclear inclusion disease (NIID) is a rare, progressive neurodegenerative disorder typically presenting in childhood.
• Juvenile parkinsonism describes parkinsonian symptoms in individuals under 20 years of age.
• Understanding NIID's natural history is crucial for early diagnosis and management.

Observation:

• A 12-year-old patient presented with progressive dysarthria, dysphagia, and clumsiness, exhibiting parkinsonism.
• Initial response to levodopa was followed by motor fluctuations, dyskinesias, psychosis, and dystonia.
• The patient later developed non-motor symptoms and died from respiratory failure.

Findings:

• Neuropathological examination confirmed NIID with characteristic eosinophilic nuclear inclusions and SUMO-1 immunoreactivity.
• The case illustrates a 10-year natural history of NIID presenting as juvenile parkinsonism.
• Key diagnostic indicators include early-onset levodopa-induced dyskinesias, gastrointestinal issues, and oculogyric crises.

Implications:

• NIID should be considered in the differential diagnosis of juvenile parkinsonism.
• Recognizing specific clinical clues can aid in earlier identification of NIID.
• This case underscores the importance of comprehensive evaluation in pediatric movement disorders.