This article discusses a case report of a patient with anti-IgLON5 disease presenting with orthostatic myoclonus, a novel manifestation. The patient experienced progressive gait difficulty, intention tremor, short-term memory decline, and sleep-related movements. Neurological examination revealed various motor abnormalities, including orthostatic myoclonus. The patient received immunotherapy and achieved meaningful remission. The article highlights the importance of considering anti-IgLON5 disease as a potential cause of orthostatic myoclonus and emphasizes the value of neurophysiological testing in distinguishing it from other conditions. [Extracted from the article]