Neuronal intranuclear inclusion disease

Abstract

Neuronal intranuclear inclusion disease (NIID), also known as neuronal intranuclear hyaline inclusion disease, is a rare neurodegenerative disorder with onset typically in childhood, although adult onset has been described. Both sporadic and familial occurrences have been reported.1,2 Presenting features of NIID are typically widespread, involving central, peripheral, and autonomic nervous systems, leading to the impression of multisystem degeneration.1 These features include parkinsonism, cerebellar ataxia, chorea, dystonia, gaze-evoked horizontal nystagmus, pyramidal tract signs, seizures, mental retardation, dementia, autonomic dysfunction, and peripheral neuropathy. Oculogyric crisis3 and early-onset l-dopa–induced dyskinesias4,5 may be a clue to diagnosis, especially if coexisting gastrointestinal dysfunction is present,2 with pseudoobstruction being relatively common. Clinical features observed in NIID are also typically observed in trinucleotide repeat disorders and therefore NIID should be even more strongly suspected after genetic testing has ruled out trinucleotide repeat disorders. Furthermore, …