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ORPHA:739

Prader-Willi syndrome

high confidenceDisorder

Also known as: Prader-Labhart-Willi syndrome

Publications

14,427

96.1th percentile

Trials

107

Interventional, condition-specific

Researchers

1,112

Distinct authors in sample

Gene link

NDN, SNRPN

Definitive

Readiness

6/6

Stages with a signal

Clinical definition (Orphanet)

A rare genetic, neurodevelopmental syndrome characterized by hypothalamic-pituitary dysfunction with severe and feeding deficits during the period followed by an excessive weight gain period with hyperphagia with a risk of severe obesity during childhood and adulthood, learning difficulties, deficits of social skills and behavioral problems or severe psychiatric problems.

How rare: 1-9 / 100 000 — about one to nine people per hundred thousand.

Orphanet entry

Cross-references

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

Additional Mondo synonyms (2)

Prader-Willi-Labhart syndrome · Willi-Prader syndrome

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 — NDN, SNRPN

  2. LiteraturePresent

    14,427 matched papers (7,120 in last 10 years) Source

  3. Phenotype characterisedPresent

    702 HPO annotations (e.g. Feeding difficulties; Neurodevelopmental delay; Small scrotum) Source

  4. Animal modelPresent

    20 genotype models (Mus musculus) Source

  5. Orphan designationPresent

    11 FDA · 9 EMA designations (11 FDA orphan-indication approvals) — e.g. cannabidiol Source

  6. Interventional trialPresent

    107 matched on ClinicalTrials.gov (16 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 (NDN, SNRPN).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

702

Associated phenotypes · MONDO:0008300

  • Feeding difficulties
  • Neurodevelopmental delay
  • Small scrotum
  • Clitoral hypoplasia
  • Hypoplastic labia minora

Showing 5 of 702 — open Monarch for the full list.

Animal models (Monarch / Alliance)

20

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)

20

Designations · 11 with FDA orphan-indication approval

  • FDA cannabidiolPrader Willi syndrome · 2020-08-21 · Not FDA Approved for Orphan Indication
  • FDA oxytocinPrader-Willi Syndrome · 2017-06-15 · Not FDA Approved for Orphan Indication
  • FDA OleoylethanolamidePrader-Willi Syndrome · 2017-06-08 · Not FDA Approved for Orphan Indication
  • FDA D-tagatosePrader-Willi Syndrome · 2017-01-19 · Not FDA Approved for Orphan Indication
  • FDA setmelanotidePrader-Willi Syndrome · 2015-09-21 · Not FDA Approved for Orphan Indication
  • FDA oxytocinPrader-Willi Syndrome · 2014-11-24 · Not FDA Approved for Orphan Indication
  • FDA diazoxide cholinePrader-Willi Syndrome · 2014-05-13 · Not FDA Approved for Orphan Indication
  • FDA beloranibPrader-Willi Syndrome · 2013-01-15 · Not FDA Approved for Orphan Indication

Sources: FDA OOPD · EMA orphan designations

Open Targets candidates

22

Drugs / clinical candidates · MONDO_0008300

CTD chemicals (MyDisease.info)

1 associated chemical · 22 pathways. Therapeutic evidence is listed first when present — not a treatment recommendation.

  • Risperidone · therapeutic

Pathways: Ubiquitin mediated proteolysis; Adaptive Immune System; Cell Cycle; Immune System; SUMOylation; SUMOylation of DNA damage response and repair proteins; SUMO E3 ligases SUMOylate target proteins; Metabolism of proteins

MyDisease.info · MONDO:0008300

Literature

Is anyone studying this?

14,427

14,427 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.

14,427 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).

7,120 in the last 10 years · high confidence · 96.1th percentile (publications denominator)

Phrase hits: 11,995 · MeSH hits: 294

Open Europe PMC search

Who's working on it?

1,112

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
    Strong TV7 papers · 2026

    Foundation for Prader-Willi Research, Covina, CA, USA.

    Papers in Europe PMC
  2. 02
    Grugni G5 papers · 2026

    Experimental Laboratory for Auxo-Endocrinological Research, Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Piancavallo-Verbania, Italy.

    Papers in Europe PMC
  3. 03
    Miller JL5 papers · 2026

    University of Florida Health Shands Hospital, Gainesville, Florida.

    Papers in Europe PMC
  4. 04
    Sartorio A5 papers · 2026

    Experimental Laboratory for Auxo-Endocrinological Research, Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Piancavallo-Verbania, Italy.

    Papers in Europe PMC
  5. 05
    Schaaf CP5 papers · 2026

    Institute of Human Genetics, Heidelberg University, Heidelberg, Germany.

    Papers in Europe PMC
  6. 06
    Butler MG4 papers · 2026

    Department of Psychiatry and Behavioural Sciences, University of Kansas Medical Centre, Kansas City, KS, USA.

    Papers in Europe PMC
  7. 07
    Crinò A4 papers · 2026

    Rare Disease Unit, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy.

    Papers in Europe PMC
  8. 08
    Davey MJ4 papers · 2026

    Department of Paediatrics, Monash University, Melbourne, Australia.

    Papers in Europe PMC
  9. 09
    Fintini D4 papers · 2026

    Prader-Willi Reference Center, Endocrinology and Diabetology Unit, Bambino Gesù Children Hospital, IRCCS, Rome, Italy.

    Papers in Europe PMC
  10. 10
    Horne RSC4 papers · 2026

    Department of Paediatrics, Monash University, Melbourne, Australia.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

107

interventional trials for this specific condition

107 interventional trials matched this specific condition name; 16 currently recruiting in our sample.

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

107 interventional trials — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 98.6th percentile).

high confidence · 98.6th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

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

Observational and natural-history studies

37 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 17 · after dedupe 17 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 17 · 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 (17)

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 Prader-Willi syndrome — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

Directly listed under NPRD Group 2.

Group 2 — long-term / lifelong lower-cost interventions

NPRD envisages State Government support for dietary formulae, hormones, and other lower-cost interventions. This is a different route from the central CoE ₹50 lakh pathway; ask your state health department and a CoE which channel applies.

Central CoE funding may also apply depending on current rules — confirm with a notified Centre of Excellence. Do not assume the ₹50 lakh ceiling covers Group 2 by default. Verify

Centres of Excellence (15)
  • All India Institute of Medical Sciences (AIIMS) — New Delhi, Delhi
  • Maulana Azad Medical College — New Delhi, Delhi
  • Sanjay Gandhi Post Graduate Institute of Medical Sciences — Lucknow, Uttar Pradesh
  • Post Graduate Institute of Medical Education and Research (PGIMER) — Chandigarh, Chandigarh
  • Centre for DNA Fingerprinting & Diagnostics with Nizam’s Institute of Medical Sciences — Hyderabad, Telangana
  • King Edward Memorial Hospital — Mumbai, Maharashtra
  • Institute of Post-Graduate Medical Education and Research (IPGMER) — Kolkata, West Bengal
  • Centre for Human Genetics with Indira Gandhi Hospital — Bengaluru, Karnataka
  • Institute of Child Health and Hospital for Children (ICH & HC) — Chennai, Tamil Nadu
  • All India Institute of Medical Sciences (AIIMS) — Jodhpur, Rajasthan
  • Sree Avittam Thirunal Hospital (SAT), Government Medical College — Thiruvananthapuram, Kerala
  • All India Institute of Medical Sciences (AIIMS) — Bhopal, Madhya Pradesh
  • Regional Institute of Medical Sciences (RIMS) — Imphal, Manipur
  • All India Institute of Medical Sciences (AIIMS) — Patna, Bihar
  • Assam Medical College & Hospital — Dibrugarh, Assam

Voluntary contributions / crowdfunding (separate from CoE funding): https://rarediseases.mohfw.gov.in/

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.

("Prader-Willi syndrome" OR "Prader-Labhart-Willi syndrome" OR "Prader-Willi-Labhart syndrome" OR "Willi-Prader syndrome") OR (MESH:"Prader-Willi Syndrome") OR ("NDN syndrome" OR "NDN-related" OR "SNRPN" OR "SNRPN syndrome" OR "SNRPN-related")

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Prader-Willi Syndrome

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

"Prader-Willi syndrome" OR "Prader-Labhart-Willi syndrome" OR "Prader-Willi-Labhart syndrome" OR "Willi-Prader syndrome"

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: 107 interventional · 37 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 multi-word and distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-26T15:07:14.249Z