Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disease. Skin biopsy, as a screening method, has greatly improved the diagnostic efficiency of the disease. Recently, researchers have successfully identified that the GGC repeat expansion in the 5' region of the NOTCH2NLC gene is the causative mutation of NIID. In addition to the typical NIID phenotype presenting with episodic/progressive encephalopathy, peripheral neuropathy, and autonomic disturbance, the gene mutation had also been reported to be associated with a small portion of Alzheimer's disease, Parkinsonism, multiple system atrophy and essential tremor patients. So, the name of NOTCH2NLC-related repeat expansion disorder was proposed to include these variable phenotypes. We revisited the discovery milestones, clinical phenotype, laboratory examinations, as well as new insight into diagnosis and treatment of NIID.

Neurons; Intranuclear inclusion bodies; Trinucleotide repeat expansion; Mutation; NOTCH2NLC gene