Clinical Spectrum of NIID (Neuronal Intranuclear Inclusion Disease) (P2.184)

OBJECTIVE: To characterize the clinical features of NIID based on our 6 cases. BACKGROUND: 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. The presenting features of NIID are typically widespread, involving central, peripheral, and autonomic nervous systems, leading to the impression of multisystem degeneration. Both sporadic and familial occurrences have been reported. Recently, confirmation of intranuclear inclusions from skin biopsy samples makes it easier for the diagnosis of NIID, however, its pathomechanism is still unknown. DESIGN/METHODS: We examined six cases (two males and four females) of NIID diagnosed by confirming intranuclear inclusions on skin biopsy samples whose range of age was from 60 to 69. All cases had no family history. We conducted neurological evaluations, biological evaluations including cerebrospinal fluid (CSF), MR imaging, nerve conduction studies as well as reviewed skin biopsy samples. RESULTS: Six cases showed many kinds of symptoms including cognitive dysfunctions, parkinsonism, cerebellar ataxia, diminishing deep tendon reflexes and autonomic failures. Protein level of CSF was increased except for one case. MR images showed symmetrical hyperintensities in subcortical white matter on T2-weighted images and FLAIR whose lateral boundary showed high intensity on diffusion weighted images. All cases exhibited mild decrease of nerve conduction velocities in lower extremities in spite of no sensory complaints. Nuclei of fatty cells with inclusions showed larger in size and had frequently a vacuole in themselves. CONCLUSIONS: MR images of NIID show very characteristic features, especially on diffusion weighted images, which can makes it easier to make a diagnosis of NIID. Decreasing conduction velocity of peripheral nerve can be a surrogate marker of NIID. Disclosure: Dr. Kowa has nothing to disclose. Dr. Sekiguchi has nothing to disclose. Dr. Sekiya has nothing to disclose. Dr. Kanda has nothing to disclose. Dr. Toda has nothing to disclose.