Although the phenotype of CDKL5 mutation is similar to Rett syndrome caused by MECP2 mutation, the former is characterized by early-onset seizures and association with West syndrome.
CDKL5 mutations are a significant cause of infantile spasms and early epileptic seizures in female patients, and of a later intractable seizure disorder, irrespective of whether they have suspected Rett syndrome.
Mutations in the CDKL5 gene (also known as STK9) have recently been shown to cause early onset epilepsy and severe mental retardation (ISSX or West syndrome).
X-linked cyclin-dependent kinase-like 5 (CDKL5 or STK9) has recently been implicated in atypical Rett and X-linked West syndromes, severe neurological disorders associated with mental retardation, loss of communication and motor skills and infantile spasms and seizures in predominantly females.
Here, we report that de novo missense mutations in CDKL5 are associated with a severe phenotype of early-onset infantile spasms and clinical features that overlap those of other neurodevelopmental disorders, such as Rett syndrome and Angelman syndrome.