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.
The CDKL5 gene encodes proteins essential for normal brain function. Mutations in the gene are usually spontaneous ‘de novo’ occurrences, rather than inherited. Initially, CDKL5 mutations had been found in children diagnosed with cerebral palsy and autism, among other conditions, and the resulting disorder was classified as an early-onset seizure variant of Rett Syndrome. It is now known to be an independent clinical entity caused by mutations in a distinct X-linked gene and therefore a separate disorder with its own distinct characteristics. In January, 2020, CDKL5 Deficiency Disorder was officially awarded an ICD10 code (G40.42) by the World Health Organization, a landmark in the recognition of CDD as a distinct clinical disorder.