International 15q Day is observed worldwide every November 15 to promote awareness of neurodevelopmental disorders linked to changes in the q11-q13 region of chromosome 15, specifically Prader-Willi syndrome, Angelman syndrome, and Dup15q syndrome. These conditions share symptoms such as developmental delays, seizures, and behavioral issues, but each has distinct characteristics. For example, Prader-Willi syndrome is marked by an insatiable appetite, while Angelman syndrome is known for severe speech impairment and a happy demeanor. Dup15q syndrome is often associated with autism spectrum disorder and specific patterns of epilepsy. The day aims to educate medical professionals and the public about these syndromes, which are frequently misdiagnosed due to their rarity. Individuals can participate by learning about the conditions, sharing information, donating to relevant organizations, and raising awareness on social media.