Clinicopathological features of neuronal intranuclear inclusion disease diagnosed by skin biopsy.

Study Objectives: Neuronal intranuclear inclusion disease (NIID) is a rare progressive neurodegenerative disorder, with complex and diverse of clinical manifestations characterized by eosinophilic hyaline inclusions in neurons and somatic cells. Due to the improvement in diagnostic methods, NIID is being increasingly diagnosed.

Methods: Herein, we reported three NIID cases, which were diagnosed by skin biopsy and FMR1 gene, after DWI showed the characteristic corticomedullary junction hyperintensity. Then we reviewed all the published cases of NIID in PubMed, which were diagnosed by the same method.

Results: We discussed 15 NIID cases, including three cases diagnosed by us. The average age was 63.4 ± 14.0 years. The average time from onset of symptom to diagnosis was 5.4 ± 7.9 years. Nine cases had dementia or cognitive impairment. Three cases presented with encephalitis. Three cases showed bladder dysfunction and two cases only presented with dizziness and headache. Two cases showed acute neurological deficit mimicking stroke. All cases were diagnosed by skin biopsy, after DWI showed abnormal corticomedullary junction hyperintensity. Ten cases showed inclusions in sweat gland cells, and seven cases in adipocytes, sweat gland cells, and fibroblasts. EMG was performed in five cases, four of whom had abnormal results, showing simultaneous involvement of motor and sensory nerves.

Conclusions: The results indicated that inclusions were more easily detected in sweat gland cells in skin biopsy. The early stage of NIID could only characterized by autonomic nerve function involvement. Combined autonomic nerve dysfunction might be another relatively common manifestation in NIID.