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ORPHA:505652

CDKL5-deficiency disorder

low confidenceDisorder

Also known as: CDD

Publications

663

Trials

9

Interventional, condition-specific

Researchers

1,073

Distinct authors in sample

Gene link

CDKL5

Definitive

Readiness

3/6

Stages with a signal

Clinical definition (Orphanet)

A rare genetic neurodevelopmental disorder characterized by early-onset drug-resistant and severe neurodevelopmental impairment with major motor development delay.

How rare: How common this is has not been clearly measured.

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Additional Mondo synonyms (8)

CDKL5 early infantile epileptic encephalopathy · DEE2 · EIEE2 · developmental and epileptic encephalopathy 2, X-linked dominant · developmental and epileptic encephalopathy, 2 · early infantile epileptic encephalopathy caused by mutation in CDKL5 · epileptic encephalopathy, early infantile, 2 · epileptic encephalopathy, early infantile, type 2

Research stages

Trial readiness signals

Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”

3/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedPresent

    Definitive — CDKL5

  2. LiteraturePresent

    663 matched papers (645 in last 10 years) Source

  3. Phenotype characterisedNot checked

    Not yet enriched from Monarch / HPO

  4. Animal modelNot checked

    Not yet enriched from Monarch / Alliance

  5. Orphan designationNot checked

    FDA/EMA orphan-drug designation not enriched yet

  6. Interventional trialPresent

    9 matched on ClinicalTrials.gov (2 recruiting in sample)

Biology

Genes and phenotypes

Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.

Do we know what causes it?

Yes — we know a specific gene responsible (CDKL5).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

Not enriched in this build — Monarch phenotype joins were not run for this record.

Animal models (Monarch / Alliance)

Not enriched in this build.

Literature

Is anyone studying this?

663

663 papers have been published on this condition. That is a real research literature — still far smaller than common diseases (breast cancer: over 700,000 papers). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=5449) is 41.

663 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 41 (publications denominator n=5449).

645 in the last 10 years · low confidence

Phrase hits: 663 · MeSH hits: 14

Open Europe PMC search

Who's working on it?

1,073

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Downs J28 papers · 2026

    Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia.

    Papers in Europe PMC
  2. 02
    Leonard H27 papers · 2026

    Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia.

    Papers in Europe PMC
  3. 03
    Benke TA23 papers · 2026

    Children's Hospital Colorado, Neurology and Pharmacology, Aurora, Colorado, USA.

    Papers in Europe PMC
  4. 04
    Marsh ED22 papers · 2026

    Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.

    Papers in Europe PMC
  5. 05
    Demarest S21 papers · 2026

    School of Medicine, Children's Hospital Colorado, University of Colorado, Aurora, CO, USA.

    Papers in Europe PMC
  6. 06
    Jacoby P18 papers · 2026

    Telethon Kids Institute, Child Disability, The University of Western Australia, Perth, Western Australia, Australia.

    Papers in Europe PMC
  7. 07
    Ciani E17 papers · 2026

    Department of Biomedical and Neuromotor Sciences, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy.

    Papers in Europe PMC
  8. 08
    Medici G16 papers · 2026

    Department of Biomedical and Neuromotor Sciences, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy.

    Papers in Europe PMC
  9. 09
    Mottolese N15 papers · 2026

    Department of Biomedical and Neuromotor Sciences, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy.

    Papers in Europe PMC
  10. 10
    Loi M14 papers · 2026

    Department of Biomedical and Neuromotor Sciences, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

9

interventional trials for this specific condition

9 interventional trials matched this specific condition name; 2 currently recruiting in our sample.

Data as of 27 July 2026

9 interventional trials — more than 73% of diseases in the trials denominator have none at all (5114 of 7003; this disease is at the 91.2th percentile).

low confidence · 91.2th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

9 interventional trials matched after quoted-phrase search and title/condition post-filter.

Observational and natural-history studies

6 observational studies match this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.

Recruiting or not-yet-recruiting

Open the complete matched search on ClinicalTrials.gov

Where to find support

We do not yet link condition-specific patient organisations. These umbrella groups support undiagnosed and ultra-rare families:

India — NPRD

Last verified 2026-07-26

This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.

Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.

How we counted this

Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.

"CDKL5-deficiency disorder" OR "CDKL5 early infantile epileptic encephalopathy" OR "EIEE2" OR "developmental and epileptic encephalopathy 2, X-linked dominant" OR "developmental and epileptic encephalopathy, 2" OR "early infantile epileptic encephalopathy caused by mutation in CDKL5" OR "epileptic encephalopathy, early infantile, 2" OR "epileptic encephalopathy, early infantile, type 2"

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: CDKL5 deficiency disorder

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"CDKL5-deficiency disorder" OR "CDKL5 early infantile epileptic encephalopathy" OR "EIEE2" OR "developmental and epileptic encephalopathy 2, X-linked dominant" OR "developmental and epileptic encephalopathy, 2" OR "early infantile epileptic encephalopathy caused by mutation in CDKL5" OR "epileptic encephalopathy, early infantile, 2" OR "epileptic encephalopathy, early infantile, type 2" OR "CDKL5 deficiency disorder" OR "CDKL5"

Recall-expansion terms: CDKL5

Interventional trials matched via: both, recall-expansion (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 9 interventional · 6 observational · 1 expanded access. Only interventional studies enter the trial headline.

Query health: ok — strategies attempted: phrase, mesh, recall-expansion; with hits: phrase, mesh, recall-expansion

Run this search on ClinicalTrials.gov

Synonyms dropped by stoplist: CDD; DEE2

Confidence reasoning

  • Preferred label is short or not clearly distinctive
  • 2 synonym(s) dropped by stoplist (may under-count)
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-27T17:49:16.701Z