ORPHA:99803
Haddad syndrome
Also known as: Congenital central alveolar hypoventilation-Hirschsprung disease syndrome · Ondine-Hirschsprung disease · Ondine-Hirschsprung syndrome
Publications
109
51.2th percentile
Trials
1
Interventional, condition-specific
Researchers
605
Distinct authors in sample
Gene link
PHOX2B
Definitive
Readiness
3/6
Stages with a signal
Clinical definition (Orphanet)
Haddad syndrome is a rare disorder in which central hypoventilation syndrome (CCHS), or Ondine syndrome, occurs concurrently with Hirschsprung disease.
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.
Cross-references
Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.
- MONDO:0020493
- UMLS:C1859049
Additional Mondo synonyms (3)
congenital central alveolar hypoventilation-Hirschsprung disease syndrome · ondine-Hirschsprung disease · ondine-Hirschsprung 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.”
3/6 stages with a signal
An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.
- Gene identifiedPresent
Definitive — PHOX2B
- LiteraturePresent
109 matched papers (44 in last 10 years) Source
- Phenotype characterisedNot checked
Not yet enriched from Monarch / HPO
- Animal modelNot checked
Not yet enriched from Monarch / Alliance
- Orphan designationNot checked
FDA/EMA orphan-drug designation not enriched yet
- Interventional trialPresent
1 matched on ClinicalTrials.gov
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 (PHOX2B).
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?
109
109 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=5449) is 41.
109 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).
44 in the last 10 years · medium confidence · 51.2th percentile (publications denominator)
Phrase hits: 109 · MeSH hits: 0
Who's working on it?
605
Distinct author names in 109 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.
- 01Amiel J6 papers · 2014
Département de Génétique, Unité INSERM U-393, Hôpital Necker-Enfants Malades, 149 rue de Sèvres, 75743 Paris Cedex 15, France.
Papers in Europe PMC - 02Lyonnet S5 papers · 2006Papers in Europe PMC
- 03Munnich A4 papers · 2006Papers in Europe PMC
- 04Trochet D4 papers · 2006
Unité de Recherches sur les Handicaps Génétiques de l'Enfant, INSERM U-393, and Département de Génétique, Hôpital Necker-Enfants Malades, Paris, France.
Papers in Europe PMC - 05Chen KC3 papers · 2021
MD Anderson Cancer Centre, University of Texas, Houston, TX, 77030, USA.
Papers in Europe PMC - 06Croaker GD3 papers · 2021
Royal Alexandra Hospital for Children, Sydney, Australia.
Papers in Europe PMC - 07Goldstein AM3 papers · 2021
Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Papers in Europe PMC - 08Heuckeroth RO3 papers · 2023
Department of Pediatrics, The Children's Hospital of Philadelphia Research Institute, USA; The Perelman School of Medicine at the University of Pennsylvania, Abramson Research Center, 3615 Civic Center Boulevard, Philadelphia, PA 19104, USA. Electronic address: heuckerothr@email.chop.edu.
Papers in Europe PMC - 09Hofstra RM3 papers · 2013Papers in Europe PMC
- 10Kinney HC3 papers · 2010Papers in Europe PMC
Clinical research
Is a treatment being tested?
1
interventional trials for this specific condition
1 interventional trial matched this specific condition name; none in our sample are currently recruiting.
Data as of 27 July 2026
1 interventional trial — more than 73% of diseases in the trials denominator have none at all (5114 of 7003; this disease is at the 76.8th percentile).
medium confidence · 76.8th percentile (trials denominator)
Recruiting interventional trials
From the matched ClinicalTrials.gov set
1 interventional trials matched after quoted-phrase search and title/condition post-filter.
No currently recruiting studies in the matched set. Open the same search on ClinicalTrials.gov.
Observational and natural-history studies
2 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.
None of the matched observational studies is currently listed as recruiting.
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 2026-07-26This 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.
"Haddad syndrome" OR "Congenital central alveolar hypoventilation-Hirschsprung disease syndrome" OR "Ondine-Hirschsprung disease" OR "Ondine-Hirschsprung syndrome"
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Haddad syndrome" OR "Congenital central alveolar hypoventilation-Hirschsprung disease syndrome" OR "Ondine-Hirschsprung disease" OR "Ondine-Hirschsprung syndrome" OR "PHOX2B"
Recall-expansion terms: PHOX2B
Interventional trials matched via: 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: 1 interventional · 2 observational · 0 expanded access. Only interventional studies enter the trial headline.
Query health: ok — strategies attempted: phrase, recall-expansion; with hits: phrase, recall-expansion
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
Ingested 2026-07-27T06:18:43.859Z