Anti-IgLON5 syndrome was first described in 2014 (2) as a disorder characterized by sleep dysfunction, a progressive supranuclear palsy-like syndrome (3), movement disorders (e.g., chorea) and brainstem and hypothalamic involvement leading to dysphagia and dysarthria, with a varying degree of dysautonomic features. The gene discussed is IGLON5; the disease is Down syndrome.