CDKL5 stands for cyclin-dependent kinase-like 5, a protein whose gene is located on the X chromosome. The CDKL5 gene provides instructions for making a protein that is essential in forming the connections for normal brain development, with mutations causing a deficiency in the protein level.
Most children affected by CDKL5 deficiency (about 90 percent of whom are girls) suffer from seizures that begin in the first few months of life. Most cannot walk, talk, or feed themselves, and many are confined to wheelchairs, dependent on others for everything. Many also suffer with scoliosis, visual impairment, sensory problems, and gastrointestinal difficulties.
CDKL5 mutations have been found in children diagnosed with cerebral palsy and autism, among other conditions, and the disorder was previously classified as an early seizure variant of Rett Syndrome. Mutations in the gene are usually spontaneous occurrences, rather than inherited, and physicians do not yet know the full range of CDKL5 disorders. There are more than 1,200 documented cases of CDKL5 worldwide, with the number of identified patients increasing as genetic testing for the disorder becomes more common.