The recent identification of antibodies against IgLON5, a neuronal cell adhesion protein of unknown function, in serum and CSF of eight patients with similar symptoms was critical to discover a novel neurological disorder characterized by chronic, less often subacute development of gait instability, chorea, dysarthria, dysphagia, episodic central hypoventilation, stridor, and a previously unrecognized sleep disorder with non REM (rapid eye movement) and REM parasomnias and obstructive sleep apnea. This evidence concerns the gene IGLON5 and nervous system disorder.