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ORPHA:702

Pelizaeus-Merzbacher disease

medium confidenceDisorder

Also known as: Diffuse familial brain sclerosis · PMD · Pelizaeus-Merzbacher brain sclerosis · Sudanophilic leukodystrophy, Paelizeus-Merzbacher type

Publications

7,948

94.6th percentile

Trials

3

Interventional, condition-specific

Researchers

1,190

Distinct authors in sample

Gene link

PLP1

Definitive

Readiness

6/6

Stages with a signal

Clinical definition (Orphanet)

Pelizaeus-Merzbacher disease (PMD) is an X-linked leukodystrophy characterized by , nystagmus, , spasticity, and variable intellectual deficit. It is classified into three sub-forms based on the age of onset and severity: connatal, transitional, and classic PMD.

How rare: 1-9 / 1 000 000 — roughly one to nine people per million. In a city the size of Kolkata, perhaps a few dozen.

Orphanet entry

Cross-references

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

Additional Mondo synonyms (5)

HLD1 · Pelizaeus-Merzbacher disease, X-linked recessive · Pelizaeus-Merzbacher spectrum disorder · diffuse familial brain sclerosis · sudanophilic leukodystrophy, Paelizeus-Merzbacher type

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.”

6/6 stages with a signal

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

  1. Gene identifiedPresent

    Definitive — PLP1

  2. LiteraturePresent

    7,948 matched papers (5,179 in last 10 years) Source

  3. Phenotype characterisedPresent

    180 HPO annotations (e.g. Abnormality of the urinary system; Optic atrophy; Hypotonia) Source

  4. Animal modelPresent

    8 genotype models (Mus musculus) Source

  5. Orphan designationPartial

    1 EMA designation (none yet with FDA orphan-indication approval) — e.g. 2'-O-(2-methoxyethyl) modified antisense oligonucleotide targeting PLP1 pre-mRNA Source

  6. Interventional trialPresent

    3 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 (PLP1).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

180

Associated phenotypes · MONDO:0010714

  • Abnormality of the urinary system
  • Optic atrophy
  • Hypotonia
  • Cerebral cortical atrophy
  • Short stature

Showing 5 of 180 — open Monarch for the full list.

Animal models (Monarch / Alliance)

8

Model associations linked to this Mondo ID

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)

1

Designation · no FDA orphan-indication approval yet

  • EMA 2'-O-(2-methoxyethyl) modified antisense oligonucleotide targeting PLP1 pre-mRNATreatment of Pelizaeus-Merzbacher disease · 16/08/2023 · PositiveEMA designation

Sources: FDA OOPD · EMA orphan designations

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?

7,948

7,948 papers — among the better-studied rare conditions, though still a fraction of common-disease literature (breast cancer: over 700,000). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

7,948 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).

5,179 in the last 10 years · medium confidence · 94.6th percentile (publications denominator)

Phrase hits: 1,930 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,190

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
    Wang J10 papers · 2025

    Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China; Key Laboratory of Anesthesiology (The Fourth Military Medical University), Ministry of Education of China, Xi'an, 710032, China.

    Papers in Europe PMC
  2. 02
    Miyamoto Y9 papers · 2026

    Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan.

    Papers in Europe PMC
  3. 03
    Inoue K8 papers · 2026

    Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, 187-0031, Japan.

    Papers in Europe PMC
  4. 04
    Yamauchi J8 papers · 2026

    Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan. yamauchi@toyaku.ac.jp.

    Papers in Europe PMC
  5. 05
    Bernard G7 papers · 2026

    Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada; Department of Pediatrics, McGill University, Montréal, Québec, Canada; Department of Human Genetics, McGill University, Montréal, Québec, Canada; Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre, Montréal, Québec, Canada. Electronic address: genevieve.bernard@mcgill.ca.

    Papers in Europe PMC
  6. 06
    Jiang Y6 papers · 2026

    Department of Neurology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.

    Papers in Europe PMC
  7. 07
    Vanderver A6 papers · 2026

    Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania; Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

    Papers in Europe PMC
  8. 08
    Wolf NI6 papers · 2026

    Amsterdam Leukodystrophy Centre, Department of Child Neurology, Emma Children's Hospital, and Amsterdam Neuroscience, Amsterdam University Medical Center, Vrije Universiteit, Amsterdam 1105 AZ, the Netherlands.

    Papers in Europe PMC
  9. 09
    Ji H5 papers · 2022

    Department of Pediatrics, Peking University First Hospital, No. 1 Xi'an Men Street, West District, Beijing, 100034, China.

    Papers in Europe PMC
  10. 10
    Tonduti D5 papers · 2026

    Unit of Pediatric Neurology, C.O.A.L.A. (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Milan, Italy.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

3

interventional trials for this specific condition

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

Data as of 11 September 2026 · last trial check 28 July 2026

3 interventional trials — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 86.7th percentile).

medium confidence · 86.7th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

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

Observational and natural-history studies

5 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

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 2 · after dedupe 2 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 2 · dropped 0 · fetched 2026-07-29

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).

Uncertain / not reviewed (2)

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 Pelizaeus-Merzbacher disease — 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.

("Pelizaeus-Merzbacher disease" OR "Diffuse familial brain sclerosis" OR "Pelizaeus-Merzbacher brain sclerosis" OR "Sudanophilic leukodystrophy, Paelizeus-Merzbacher type" OR "Pelizaeus-Merzbacher disease, X-linked recessive" OR "Pelizaeus-Merzbacher spectrum disorder") OR ("PLP1" OR "PLP1 syndrome" OR "PLP1-related")

Run this search on Europe PMC

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

"Pelizaeus-Merzbacher disease" OR "Diffuse familial brain sclerosis" OR "Pelizaeus-Merzbacher brain sclerosis" OR "Sudanophilic leukodystrophy, Paelizeus-Merzbacher type" OR "Pelizaeus-Merzbacher disease, X-linked recessive" OR "Pelizaeus-Merzbacher spectrum disorder"

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

Study-type breakdown: 3 interventional · 5 observational · 0 expanded access. Only interventional studies enter the trial headline.

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

Run this search on ClinicalTrials.gov

Synonyms dropped by stoplist: PMD; HLD1

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • 2 synonym(s) dropped by stoplist (may under-count)
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-26T14:57:17.539Z