MEF2C Awareness Day is observed worldwide every May 14 to highlight a group of rare genetic disorders caused by mutations in the MEF2C gene, located on the long arm of chromosome 5. The day aims to inform the public about MEF2C haploinsufficiency syndrome, a severe form of autism spectrum disorder characterized by symptoms such as global developmental delay, intellectual disability, and early-onset seizures. The date was chosen in reference to the gene's chromosomal location, 5q14.3. Organizations such as the MEF2C Foundation UK, the US MEF2C Foundation, and the MEF2C Family Foundation support this observance. Participants can engage by learning about the disorder, donating to relevant organizations, wearing blue to show solidarity, and using the hashtag #MEF2CAwarenessDay on social media. The management of MEF2C-related disorders is supportive, focusing on therapies and lifelong care.