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ORPHA:99802

Hemimegalencephaly

low confidenceDisorder

Also known as: Unilateral megalencephaly

Publications

2,345

Trials

2

Interventional, condition-specific

Researchers

1,490

Distinct authors in sample

Gene link

—

Readiness

2/6

Stages with a signal

Clinical definition (Orphanet)

Hemimegalencephaly is a rare cerebral characterized by overgrowth of all or part of a cerebral hemisphere, often with ipsilateral severe cortical or dysgenesis, white matter hypertrophy and dilated lateral ventricle, presenting in early infancy with hemiparesis, severe psychomotor retardation and intractable . Hemimegalencephaly may be an isolated finding or associated with other syndromes such as angioosteohypertrophic syndrome, epidermal nevus syndrome and Ito hypomelanosis. Management includes seizure control by antiepileptic medications and early hemispherectomy.

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 (1)

unilateral megalencephaly

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.”

2/6 stages with a signal

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

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    2,345 matched papers (1,384 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

    2 matched on ClinicalTrials.gov (1 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?

Not yet — the cause hasn't been pinned down in GenCC.

No strong gene–disease assertion joined for this Orphanet entity.

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?

2,345

2,345 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.

2,345 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).

1,384 in the last 10 years · low confidence

Phrase hits: 2,345 · MeSH hits: 63

Open Europe PMC search

Who's working on it?

1,490

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
    Chen H7 papers · 2025

    Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, 200011, People's Republic of China.

    Papers in Europe PMC
  2. 02
    Hua C6 papers · 2025

    Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, 200011, People's Republic of China. worson78@163.com.

    Papers in Europe PMC
  3. 03
    Lin X6 papers · 2025

    Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, 200011, People's Republic of China. linxiaoxi@126.com.

    Papers in Europe PMC
  4. 04
    Sun B6 papers · 2025

    Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, 200011, People's Republic of China.

    Papers in Europe PMC
  5. 05
    Baldassari S5 papers · 2024

    Inserm, CNRS, APHP, Institut du Cerveau - Paris Brain Institute - ICM, Hôpital de La Pitié Salpêtrière, Sorbonne Université, Paris, France.

    Papers in Europe PMC
  6. 06
    Baulac S5 papers · 2024

    Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, 75013 Paris, France.

    Papers in Europe PMC
  7. 07
    Fallah A5 papers · 2024

    From the The Warren Alpert Medical School of Brown University (J.-S.C.), Providence, RI; Department of Neurosurgery (W.B.H.), University of Colorado Anschutz, Aurora; Department of Neurosurgery (K.J.W., H.W.P., A.F.), University of California Los Angeles; Department of Neurosurgery (H.W.P.), University of Pittsburgh Medical Center, PA; Department of Medicine (C.-H.T.), University of California Los Angeles; Department of Neurosurgery (A.G.W.), Université de Montréal, Quebec, Canada; and Department of Pediatrics (A.F.), University of California Los Angeles. afallah@mednet.ucla.edu.

    Papers in Europe PMC
  8. 08
    Gao W5 papers · 2025

    Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, 200011, People's Republic of China.

    Papers in Europe PMC
  9. 09
    Anwar T4 papers · 2026

    Neurology, Children's National Hospital, Washington, District of Columbia, USA.

    Papers in Europe PMC
  10. 10
    Kratimenos P4 papers · 2026

    Neonatology, Children's National Hospital, Washington, District of Columbia, USA.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

2

interventional trials for this specific condition

2 interventional trials matched this specific condition name; 1 currently recruiting in our sample.

Data as of 27 July 2026

2 interventional trials — more than 73% of diseases in the trials denominator have none at all (5114 of 7003; this disease is at the 82.4th percentile).

low confidence · 82.4th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

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

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.

"Hemimegalencephaly" OR "Unilateral megalencephaly"

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Hemimegalencephaly

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

"Hemimegalencephaly" OR "Unilateral megalencephaly"

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

Study-type breakdown: 2 interventional · 0 observational · 0 expanded access. Only interventional studies enter the trial headline.

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

Run this search on ClinicalTrials.gov

Confidence reasoning

  • Preferred label is short or not clearly distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus
  • Publication count (2345) is extremely high with unknown/missing prevalence — treat as possible over-matching, not proven research intensity

Ingested 2026-07-27T06:18:33.784Z