Disease Directory CDKL5 Deficiency Disorder
Neurological

CDKL5 Deficiency Disorder

Also known as: CDD, CDKL5 epileptic encephalopathy, early-onset seizure variant of Rett syndrome, X-linked infantile spasm syndrome

Prevalence

1-9 per 100,000 (Orphanet)

Onset

Infantile

Type

X-linked dominant genetic (de novo in most cases)

Gene

CDKL5

About CDKL5 Deficiency Disorder

CDKL5 deficiency disorder is caused by mutations in CDKL5 (cyclin-dependent kinase-like 5), an X-linked gene encoding a kinase critical for synapse formation and function. Onset occurs in the first months of life with seizures that are typically severe, frequent, and highly refractory to antiseizure medications. Additional features include hypotonia, absence of purposeful hand use, limited or absent speech, and stereotyped hand movements. While previously considered a Rett variant, CDD is now recognized as a distinct disorder.

Common Clinical Features

Early-onset refractory seizures Hypotonia Absent or limited hand use Absent speech Cortical visual impairment Stereotyped hand movements Scoliosis

Clinical Trial Eligibility Tips

What to know before applying to CDKL5 Deficiency Disorder trials.

CDKL5 pathogenic variant confirmed on sequencing (hemizygous in males, heterozygous in females) is required for all trials

Baseline seizure frequency diary over minimum 3 months documenting seizure types and frequency is required

Prior antiseizure medication trials (number and response) are documented to confirm refractory status for interventional trials

CDKL5-specific functional assessment tools (CSBS, Bayley-III adapted, CDD-specific scales) are the primary outcome measures

Patient Resources

Patient Organization

International Foundation for CDKL5 Research

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Natural History Registry

InternationalCDKL5 Registry

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Orphanet

European reference resource for rare diseases (ORPHA:505652)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

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Find recruiting CDKL5 Deficiency Disorder trials

Search 500,000+ studies from ClinicalTrials.gov, filtered for CDKL5 Deficiency Disorder. Updated daily.

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