Overview
CDKL5 deficiency disorder (CDD), sometimes called CDKL5 disorder or early-onset seizure variant of Rett syndrome, is a rare brain condition caused by changes (mutations) in the CDKL5 gene. This gene gives the body instructions for making a protein that is important for normal brain development and function. When this protein does not work properly, it leads to serious problems with brain activity. The condition mainly affects babies and young children. The most noticeable sign is seizures that start very early in life, often in the first few months. These seizures can be very hard to control, even with multiple medications. Children with CDD also have significant developmental delays, meaning they may not reach milestones like sitting, walking, or talking at the expected ages. Many children have very limited or no ability to speak and need help with daily activities throughout their lives. Other common features include problems with muscle tone (muscles may be too floppy or too stiff), difficulty with hand use, vision problems, sleep disturbances, and gastrointestinal issues like constipation. While there is currently no cure, treatments focus on managing seizures and supporting development through therapies. Research into targeted treatments is actively ongoing, giving families reason for hope.
Also known as:
Key symptoms:
Frequent and hard-to-control seizures starting in early infancySevere intellectual disabilityLittle or no ability to speakDifficulty or inability to walk independentlyPoor muscle tone (floppy muscles) or stiff musclesLimited purposeful hand useVision problems or difficulty tracking objects with the eyesSleep disturbances and irregular sleep patternsConstipation and other digestive problemsRepetitive hand movements or hand wringingBreathing irregularitiesScoliosis (curved spine) in some childrenFeeding difficulties, especially in infancy
Clinical phenotype terms (50)— hover any for plain English
X-linked dominant
Carried on the X chromosome; a single copy can cause the condition
Infantile
Begins in infancy, roughly 1 month to 2 years old
FDA & Trial Timeline
8 eventsImmedica Pharma AB — PHASE3
Gruppo Oncologico Italiano di Ricerca Clinica — PHASE2
University of Milan — NA
Loulou Foundation
Zogenix, Inc. — PHASE3
Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins — PHASE1
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
1 availableZtalmy
Treatment of seizures associated with CDKL5-deficiency disorder (CDD) in patients 2 years of age and older. Ganaxolone is a neuroactive steroid GABAA receptor modulator.
Rare Disease Specialist
Treatment Centers
8 centersWashington University
📍 St Louis, Missouri
👤 Sawa M Ito, MD, PhD
👤 Anthony A. Amato, MD
Stanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🏥 NORDBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
Travel Grants
No travel grants are currently matched to CDKL5-deficiency disorder.
Community
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Start the conversation →Latest news about CDKL5-deficiency disorder
Disease timeline:
New recruiting trial: Targeting the Gut to Improve Seizure Control in CDKL5 Deficiency Disorder (CDD)
A new clinical trial is recruiting patients for CDKL5-deficiency disorder
New recruiting trial: International CDKL5 Clinical Research Network
A new clinical trial is recruiting patients for CDKL5-deficiency disorder
New trial: Immune Disorder HSCT Protocol
Phase PHASE2 trial recruiting. Transplant preparative regimen of alemtuzumab, fludarabine, thiotepa, and melphalan
New trial: International CDKL5 Registry
Phase NA trial recruiting. Survey Instrument
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What anti-seizure medications do you recommend starting with, and what is the plan if they do not work?,Should we consider the ketogenic diet, and how would we get started safely?,What therapies (physical, occupational, speech) should my child be receiving, and how often?,Are there any clinical trials for CDD that my child might be eligible for?,What signs should prompt me to call emergency services or use a rescue medication?,How often should my child be monitored for complications like scoliosis or vision problems?,What support services and patient organizations are available to help our family?
Common questions about CDKL5-deficiency disorder
What is CDKL5-deficiency disorder?
CDKL5 deficiency disorder (CDD), sometimes called CDKL5 disorder or early-onset seizure variant of Rett syndrome, is a rare brain condition caused by changes (mutations) in the CDKL5 gene. This gene gives the body instructions for making a protein that is important for normal brain development and function. When this protein does not work properly, it leads to serious problems with brain activity. The condition mainly affects babies and young children. The most noticeable sign is seizures that start very early in life, often in the first few months. These seizures can be very hard to control,
How is CDKL5-deficiency disorder inherited?
CDKL5-deficiency disorder follows a x-linked dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does CDKL5-deficiency disorder typically begin?
Typical onset of CDKL5-deficiency disorder is infantile. Age of onset can vary across affected individuals.
Are there clinical trials for CDKL5-deficiency disorder?
Yes — 5 recruiting clinical trials are currently listed for CDKL5-deficiency disorder on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat CDKL5-deficiency disorder?
25 specialists and care centers treating CDKL5-deficiency disorder are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.