Asthma-like bronchodilator responsiveness in patients with neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative condition characterized by the presence of intranuclear inclusions in neuronal and visceral cells. Patients with NIID can present respiratory symptoms; however, data on pulmonary functions in NIID are lacking. This study investigated the respiratory conditions in NIID patients diagnosed with histopathological and genetic studies. We conducted two spirometries before and after administrating the bronchodilator in NIID patients with asthmatic histories or symptoms. We statistically compared pre- and post-measured values including forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), and peak expiratory flow (PEF). Before two spirometries, we also measured fractional concentration of exhaled nitric oxide (FeNO), if possible. Of the 51finally enrolled patients, 17 (33.3%, 95% CI 20.8% to 47.9%) patients had asthmatic histories or symptoms, and 14 patients received two spirometries. After administrating the bronchodilator, FEV₁ and PEF significantly increased by 150 mL (6.01%, p = 0.002) and 260 mL/s (6.72%, p = 0.017), respectively. The median (interquartile range) of FeNO measured in nine patients was 15 (10-21) ppb. Patients with NIID have airflow reversibility like asthma. This condition appears to be less associated with airway inflammation and may be related to autonomic dysfunction.