CDKL5 Australia

This page has not yet been reviewed by our Scientific and Medical Advisory Committee. Content is written by parent volunteers and may not reflect current medical guidelines.

About CDKL5

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What is CDKL5?

CDKL5 (cyclin-dependent kinase-like 5) is a gene that helps the brain develop and work properly. When this gene has a change (sometimes called a mutation or variant), it can cause a condition called CDKL5 Deficiency Disorder, or CDD.

CDD is a rare genetic condition. It affects how the brain develops and can cause seizures that start early in life — often in the first weeks or months.

CDKL5 the gene, CDD the condition

You might hear both terms used. Here is the simplest way to think about it:

  • CDKL5 is the name of the gene.
  • CDKL5 Deficiency Disorder (CDD) is the name of the condition that happens when this gene does not work as expected.

Some older resources may refer to it as “CDKL5 disorder” or “CDKL5 epilepsy.” The internationally recognised name is CDKL5 Deficiency Disorder.

How does CDD affect children?

Every child with CDD is different. Some common features include:

  • Seizures — often the first sign, sometimes starting in the first weeks of life. Seizures can be frequent and difficult to control.
  • Developmental differences — most children have significant delays in sitting, walking, and communication.
  • Cortical visual impairment (CVI) — many children have difficulty processing what they see, even though their eyes may be healthy.
  • Movement and muscle tone — some children have low muscle tone (hypotonia) or involuntary hand movements.

There is no cure for CDD today, but therapies, medications, and support can improve quality of life. Research is active and moving faster than ever.

How common is CDD?

CDD is rare. It is estimated to affect between 1 in 40,000 and 1 in 60,000 live births. Because awareness has grown recently, many people are being diagnosed now who were previously undiagnosed or misdiagnosed.

CDD affects all genders, though it was originally identified more often in girls. Boys can also be affected.

What does CDKL5 Australia do?

CDKL5 Australia is a community association run by Australian families affected by CDD. We are here to:

  • Connect families — so no one navigates this journey alone.
  • Provide plain-language information — written by parents, reviewed by clinicians.
  • Signpost research and clinical trials — so families can make informed choices.
  • Be a credible Australian contact for hospitals, clinicians, and researchers.

We are not a research foundation. We work alongside the Australian Foundation for CDKL5 Research (AFCR) and the International Foundation for CDKL5 Research (IFCR), who fund and coordinate research programs.