Adult-Type Neuronal Intranuclear Inclusion Disease with Limb Tremor Onset: Case Report and Literature Review

Abstract

Abstract Background: Neuronal intranuclear inclusion disease (NIID) is a slowly progressing neurodegenerative disorder characterized by pathological features and eosinophilic intranuclear inclusions found in the central and peripheral nervous systems as well as in visceral organs. Herein, we report the case of a 62-year-old woman who presented with limb tremors and gradually developed cognitive impairment and unresponsiveness. Case presentation: A 62-year-old woman was admitted to our hospital because of limb tremors for 7 years, along with mental disorders,slow reactions, and gait instability for 5 years. Brain magnetic resonance imaging revealed high-intensity signals in the corpus callosum and corticomedullary junction on diffusion-weighted imaging. Additionally, fluid-attenuated inversion recovery sequences showed high-intensity signals in the bilateral cerebellar vermis and middle cerebellar peduncle. Next, cerebrospinal fluid examination indicated a pressure of 95 mmH2O, positive Pandy’s test, glucose level of 4.0 mmol/L, protein level of 1100 mg/L, and chloride level of 122 mmol/L. Other laboratory tests showed no significant abnormalities. We considered a diagnosis of NIID. Subsequently, a skin biopsy was performed 10 cm above the left lateral malleolus. P62-immunoreactive abnormal material was confirmed in individual fibroblasts. Ultrathin sectioning and imaging revealed spherical, lightly stained, short filamentous inclusion structures in fibroblast nuclei. Genetic testing found pathogenic repetitions of GGC in NOTCH2NLC. Conclusion: NIID is a rare clinically heterogeneous disease. In clinical work, a diagnosis of NIID should be considered when patients present predominantly with limb tremors and persistent abnormal high-intensity signals in the corpus callosum on diffusion-weighted imaging; NIID should especially be considered when patients do not demonstrate tendon reflexes. Long-term follow-up should be conducted to confirm the diagnosis, treatment, and prognosis of the disease.