What is it?

CDKL5 (cyclin-dependent kinase-like 5) deficiency is a disorder that is characterized by seizures beginning in infancy, followed by severe neuro-developmental impairment.1

What causes it?

CDKL5 deficiency is caused by a mutation (change) in a person’s CDKL5 gene on the X chromosome, which provides instructions for making a protein that is essential for brain development and function.1

What are some of the common symptoms?1

  • Early-onset, medication-resistant seizures (epilepsy)
  • Developmental delay
  • Intellectual disability
  • Severe speech impairment
  • Movement and balance problems (ataxia)
  • Vision problems (cortical visual impairment)
  • Small head size (acquired microcephaly)

How many people have it?

CDKL5 deficiency affects an estimated 1 in 40,000 to 60,000 newborns (primarily girls) globally.1

Common Names for CDKL5 Deficiency1

  • CDD
  • CDKL5 disorder
  • CDKL5 encephalopathy
  • CDKL5-related epilepsy
  • CDKL5-related epileptic encephalopathy
  • Early infantile epileptic encephalopathy 2

1CDKL5 deficiency disorder. Nation Institutes of Health: Genetics Home Reference Website. https://ghr.nlm.nih.gov/condition/cdkl5-deficiency-disorder#. Published August 17, 2020. Accessed September 10, 2020.

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