CDKL5 and craniodiaphyseal dysplasia: In addition, Cdkl5-/y transgenic mice were used as a model for the cyclin-dependent kinase-like 5 (Cdkl5) deficiency disorder (CDD) caused by loss of function mutation in the X-linked Cdkl5. Both diseases are associated with abnormalities in the neuronal architecture in hippocampal and cortical neurons, including simpler dendritic arbors and reduced dendritic lengths starting already at very early stages during development [16,17,36] [21,22,37,38].