The CDKL5 gene encodes an enzyme belonging to the serine/threonine kinase family. The enzyme is responsible for the phosphorylation of MECP2, a protein involved in the maintenance of synapses between neurons. While the other targets of the CDKL5 kinase are not yet known, the enzyme is believed to play a role in neuron migration, dendrite morphogenesis and axon extension.
The gene has been implicated in Epileptic Encephalopathy, Early Infantile, 2 (EIEE2), a neurologic disorder characterized by severe global developmental delay, infantile-onset seizures and mental retardation.
The CDKL5 gene is located on the short arm of the X chromosome at position Xp22.13. It spans a length of 235 kb of DNA and its coding sequence is spread across 23 exons. The protein encoded by the gene has a molecular mass of 115 kDa and consists of 1030 amino acids. An additional isoform of the CDKL5 protein exists due to alternative splicing and contains 960 amino acids. The gene is found to be expressed in the brain, lung, kidney, prostate, ovary, placenta, pancreas and testis.
Variants associated with EIEE2 include missense mutations, slice site mutations, deletions and insertions that either alter the function of the CDKL5 protein or result in its absence.