International CDKL5 Day is observed worldwide every June 17 to raise awareness about CDKL5 deficiency disorder (CDD), a rare genetic disorder that leads to neurodevelopmental disabilities. This day was established in honor of Glyn Boltwood, who passed away on this date in 1997; his DNA was crucial in the discovery of CDD. The CDKL5 gene, responsible for this disorder, was identified in 2004 by an Australian research team. CDD primarily affects females due to its location on the X chromosome, with symptoms including seizures, developmental delays, and motor impairments. The day aims to support patients and their families, provide necessary resources, and promote research into CDD. Observances include educational events and initiatives to inform the public about the challenges faced by those affected by this condition.