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Neuromuscular diseases

CDKL5 deficiency disorder (CDD)

A severe epilepsy and developmental disorder that begins in infancy. Seizures begin in the first months. The development of movement, speech and vision is affected.

Not part of the panel of Türkiye's National Newborn Screening Programme (heel-prick test). Source

Orphanet has a guideline for emergency doctors for this disease (language: French, Spanish). See on Orphanet

Prepare an emergency card

This page is translated from the Turkish original.

This disease is followed through the “Neuromuscular diseases” group.

Understanding the disease

This section has not yet been reviewed by a physician. It summarises patient information from sources such as MedlinePlus, Orphanet and the NHS in plain language. The disease can differ from person to person; talk to your doctor about diagnosis and treatment.

What happens in this disease?

The CDKL5 gene makes a protein needed for brain development. A change in this gene reduces the protein or disrupts how it works. As a result, brain development is affected. It used to be considered a type of Rett syndrome; it is now a separate disease.

Which symptoms can occur?

Seizures usually begin in the first 3 months. About 90% of those diagnosed are girls.

  • Frequent seizures that are hard to treat (every day in most)
  • Severe developmental delay, little or no speech
  • Delay in sitting and walking; about one third walk on their own
  • Vision problems caused by the brain (in most)
  • Repetitive hand movements, teeth grinding
  • Sleep problems
  • Feeding difficulties, constipation and reflux
  • Episodes of irregular breathing (sometimes)

How is it diagnosed?

The diagnosis is made by assessing the symptoms and with a genetic test. The genetic test shows the change in the CDKL5 gene. The same test is used for girls and boys.

Treatment and care

There is an approved medicine treatment specific to the disease for seizures. This treatment is used from two years of age. Many specialists work together on care. These include neurology, nutrition, sleep, physiotherapy, occupational therapy and speech therapy. Regular follow-up is important. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

The disease is X-linked. In almost all cases, it is not passed on from the parents but appears through a new gene change. Very rarely, the mother also carries this change. Then the chance of passing it on is 1 in 2 in each pregnancy. Genetic counselling clarifies the family's risk.

Source: MedlinePlus Genetics: CDKL5 deficiency disorder · GeneReviews: CDKL5 Deficiency Disorder

Key facts

How is it inherited?
X-linked dominant
When does it usually start?
Infancy, Newborn period
Gene(s) involved
CDKL5

These facts are taken from Orphanet and MedlinePlus records (last checked: October 7, 2026). Frequency values are approximate ranges.

You are not alone: patient associations in Türkiye

Non-profit patient and family organizations in Türkiye working on this disease or disease group. Links are for information; Doktorclub is not affiliated with these organizations and does not endorse them.

We could not find a patient association specific to this disease.

For all rare diseases: Nadir Hastalıklar Federasyonu

Guides related to this disease

  • Rare disease at school · Telling the school, medicines and emergency plan, inclusion and BEP, support education room, absences, LGS/YKS arrangements, peer bullying.

Support and help

Doktorclub does not diagnose, recommend treatments or refer you to hospitals or doctors. These pages are meant to help you talk with your doctor.

News about CDKL5 deficiency

Clinical trials (ClinicalTrials.gov)

A clinical trial is a regulated study that tests whether a new treatment is safe and whether it works, in patients who volunteer. Most trials look for a certain age, genetic change and health condition. Taking part is voluntary.

This list is not a treatment recommendation. Treatments tested in phase 1–3 trials are investigational (experimental): their efficacy and safety have not yet been proven and they are not approved treatments. Taking part depends on each trial’s criteria and a physician’s assessment; the first step is to talk to the doctor who manages your care.

Questions you can ask your doctor

  • Could this trial be suitable for us?
  • If we take part, how would current treatment and check-ups be affected?
  • Where does the trial take place, and how are travel and accommodation handled?
  • What happens if we want to leave the trial?

ClinicalTrials.gov lists 3 active interventional studies for this disease. None is recruiting right now; none has a site in Türkiye. Last checked: October 7, 2026.

Selected records (studies with a site in Türkiye first):

See all studies on ClinicalTrials.gov · Joining clinical trials

Neuromuscular diseases: other news

Medical codes (for talking with your doctor and finding sources)

These codes identify the disease in international classifications and databases. They can help when you talk with your doctor or look for reliable sources.

Orphanet code: ORPHA:505652

No matching ICD-11 entry was found.

Codes checked against WHO ICD-11 and Orphanet on October 7, 2026.

This page provides general information and does not replace diagnosis or treatment. Talk to your doctor about symptoms, diagnosis and treatment.

The information on these pages is for general information only and does not replace medical advice. Talk to your doctor about diagnosis and treatment decisions. In an emergency in Türkiye, call 112.

Every update is based on an open source and labeled with its level of evidence. No advertising and no drug brand names. Our scientific principles

This page was translated from Turkish by the Doktorclub editorial team.