Gelastic spells in Angelman Syndrome, when laughter isn't funny

Angelman syndrome (AS) is a neurodevelopmental syndrome characterized by people with a characteristic happy demeanor, impaired expressive communication, sleep disruptions, and a variety of paroxysmal events, including seizures and movement disorders. Herein, we report three cases, one child and two adults with AS, of gelastic (laugh-related) spells. The phenomenology in all three is most consistent with gelastic syncope. A fourth example demonstrating transient breath-holding while laughing is included for reference. We subsequently review the differential for gelastic spells in AS, including seizures and cataplexy, and expound on the importance of their identification in the context of risk factors for cardiac arrhythmia. This work adds gelastic syncope to the list of paroxysmal events in AS and may serve to inform providers and parents of this phenotype and provide guidance for subsequent evaluation and treatment if indicated.