Genetic and Pathological Characteristic Patterns of a Family With Neuronal Intranuclear Inclusion Disease

Neuronal intranuclear inclusion disease (NIID) is a rare, progressive neurodegenerative disorder. This study aimed to investigate clinical, imaging, genetic, and dermatopathological characteristics of a family with adult-onset NIID. The proband was a 62-year-old woman with 3 brothers and 2 sisters. Of these, 4 had symptoms of paroxysmal visual field defect, extrapyramidal symptoms, dysautonomia, emotional changes, and cognitive dysfunction. Genetic examination revealed no abnormality related to cerebrovascular diseases. More than 200 CGG repeats of FMR1 gene cause fragile X-associated tremor/ataxia syndrome (FXTAS) whereas repeats of the proband were found 29 times, which excluded FXTAS. Quantitative reverse transcription polymerase chain reaction (PCR) and GC-rich-PCR identified an expanded GGC repeat (with ∼100 repeats) in the 5' region of NOTCH2NLC in the patient and her 2 younger brothers. Pathological examination found eosinophilic intranuclear inclusions inside adipocytes, fibrocytes, and sweat gland cells. Immunohistochemistry and immunofluorescence staining revealed positive staining for ubiquitin and p62. The detailed pathological and genetic features of this NIID family provide a valuable contribution to the existing knowledge base of this rare disorder.