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ORPHA:83473

Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome

high confidenceDisorder

Also known as: MPPH syndrome

Publications

64

43.9th percentile

Trials

0

Interventional, condition-specific

Researchers

552

Distinct authors in sample

Gene link

—

Readiness

3/6

Stages with a signal

Clinical definition (Orphanet)

A rare syndrome with a central nervous system as a major feature characterized by macrocephaly, megalencephaly, bilateral perisylvian polymicrogyria, variable degrees of ventriculomegaly/hydrocephalus, and , oromotor dysfunction, , , and facial features (such as frontal bossing, low-set ears, a flat nasal bridge, and high-arched palate). Postaxial polydactyly of one or more extremities is also common.

How rare: <1 / 1 000 000 — fewer than one in a million. In a city the size of Kolkata, that might mean on the order of fifteen people.

Orphanet entry

Cross-references

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

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

No specific-condition interventional trial, but broader-category trials exist — discuss eligibility with a clinician.

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    64 matched papers (37 in last 10 years) Source

  3. Phenotype characterisedPresent

    66 HPO annotations (e.g. Absent speech; Global developmental delay; Severe intellectual disability) Source

  4. Animal modelNot found

    No Alliance genotype “model of” associations via Monarch for these Mondo IDs

  5. Orphan designationNot found

    No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source

  6. Interventional trialPartial

    None under the specific name; 122 for broader category hydrocephalus

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)

66

Associated phenotypes · MONDO:0019375

  • Absent speech
  • Global developmental delay
  • Severe intellectual disability
  • Prominent forehead
  • Ventriculomegaly

Showing 5 of 66 — open Monarch for the full list.

Animal models (Monarch / Alliance)

None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.

Monarch fetch 2026-07-29

Therapies

Designations, candidates, and chemicals

FDA OOPD and EMA orphan designations, Open Targets clinical candidates, and CTD chemical associations via MyDisease.info. These never change the interventional-trial headline.

Orphan designation (FDA · EMA)

No designation matched this disease via UMLS or preferred name on the FDA OOPD mirror or EMA orphan register. Absence here is not proof that none exists under another wording.

Open Targets candidates

No drugs or clinical candidates returned for this Mondo ID on Open Targets.

CTD chemicals (MyDisease.info)

No CTD chemical associations returned for this Mondo ID.

Literature

Is anyone studying this?

64

64 papers have ever been published on this condition (under this name). For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

64 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 59 (publications denominator n=3967).

37 in the last 10 years · high confidence · 43.9th percentile (publications denominator)

Phrase hits: 64 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

552

Distinct author names in 64 sampled papers — named people below.

Who's working on it?

No interventional trial matched this name; these authors publish on it in the sampled literature — a practical starting point for contact.

  1. 01
    Dobyns WB11 papers · 2021

    Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA.

    Papers in Europe PMC
  2. 02
    Mirzaa GM8 papers · 2022

    Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA.

    Papers in Europe PMC
  3. 03
    Graham JM Jr4 papers · 2022

    Department of Pediatrics, Cedars-Sinai Medical Center, Harbor-UCLA Medical Center, David Geffen School of Medicine Los Angeles, California, USA.

    Papers in Europe PMC
  4. 04
    Guerrini R4 papers · 2017

    Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, A. Meyer Children's Hospital, Florence, Italy.

    Papers in Europe PMC
  5. 05
    Barkovich AJ3 papers · 2015

    Department of Radiology and Biomedical Imaging, Neurology, Pediatrics, and Neurosurgery, University of California, San Francisco, San Francisco, California 94143-0628.

    Papers in Europe PMC
  6. 06
    Collins S3 papers · 2017

    Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA.

    Papers in Europe PMC
  7. 07
    Keppler-Noreuil KM3 papers · 2022

    National Human Genome Research institute, National Institutes of Health, Bethesda, Maryland

    Papers in Europe PMC
  8. 08
    Mirzaa G3 papers · 2018

    Arabian Gulf University, College of Medicine and Medical Sciences, Manama, Bahrain.

    Papers in Europe PMC
  9. 09
    Parker VE3 papers · 2022

    The University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, UK

    Papers in Europe PMC
  10. 10
    Semple RK3 papers · 2022

    Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

0

interventional trials for this specific condition

No interventional trial testing a treatment matched this specific condition name on ClinicalTrials.gov (observational studies and pan-disease registries are listed separately when present). 122 trials are registered for hydrocephalus, the broader category — shown separately because they may or may not enrol this specific subtype.

Data as of 11 September 2026 · last trial check 11 September 2026

No matched interventional trials. This is true for 77.2% of diseases in the trials denominator (5501 of 7126). Here are the researchers publishing on it.

high confidence · 38.6th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

No interventional trial testing a treatment was found for this specific condition name on ClinicalTrials.gov.

122 interventional trials matched hydrocephalus, the broader category — listed below. Those studies are not counted in the condition-specific total.

Broader category: hydrocephalus

122

Interventional trials for the parent category, exclusive of NCT IDs already counted above. Eligibility for this subtype is not guaranteed.

Worth raising with a clinician. How we count trials.

Recruiting under the broader category

Other registries (secondary)

Broader net from EU CTIS, ISRCTN, and ICTRP when available — deduped against ClinicalTrials.gov IDs already counted above. Dual-model LLM relevance gates what we keep. These rows are not added to the interventional headline.

raw 0 · after dedupe 0 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 0 · dropped 0 · fetched 2026-07-30

Source notes: ictrp: Error: ICTRP public search unavailable (WHO portal is SPA-only; SOAP needs partnership). Tried: https://apps.who.int/tri

No secondary-registry studies passed dual-model relevance for this condition name (after dedupe).

Where to find support

Condition-specific patient organisations, when Orphanet lists them, are on the disease’s Orphanet page. We also link umbrella groups that support undiagnosed and ultra-rare families.

Orphanet entry for Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome — check Associations / patient organisations on that page.

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.

"Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome" OR "MPPH syndrome"

Run this search on Europe PMC

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

"Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome" OR "MPPH syndrome"

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

Parent-category trials query:

"hydrocephalus"

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

Run this search on ClinicalTrials.gov

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-27T02:38:07.663Z