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Haddad syndrome is a rare congenital disorder in which congenital central hypoventilation syndrome (CCHS), or Ondine syndrome, occurs concurrently with Hirschsprung disease.
Features include very common findings: Strabismus, Failure to thrive, Small for gestational age, and Aganglionic megacolon and others; and common findings: Intellectual disability, Seizure, Low muscle tone (hypotonia), and Gastroesophageal reflux. 18 total HPO annotations.
Organ System | Phenotype Count | Example Features |
|---|---|---|
Brain and nerves | 3 | Problems with involuntary body functions (abnormal autonomic nervous system physiology), Intellectual disability, Seizure |
Phenotype severity distribution: 8 very common features, 4 common features.
Estimated prevalence: <1 in 1,000,000 (VERY_RARE).
No clinical trials have been registered for Haddad syndrome.
10 publications have been identified in PubMed for Haddad syndrome. Research spans Case Report / Case Series (30%), Basic Science / Preclinical (30%), and Clinical Trial Publication (20%).
Research Type | Count | % of Total |
|---|---|---|
Patient case studies | 3 | 30% |
Data assembled from 4 of 12 sources · Last updated Sep 19, 2026, 1:55 PM UTC
European rare disease database
Genetic and Rare Diseases Info Center
Common questions about Haddad syndrome
Lungs and breathing | 2 | Central hypoventilation, Central sleep apnea |
Eyes | 1 | Strabismus |
Growth and development | 1 | Failure to thrive |
Muscles | 1 | Low muscle tone (hypotonia) |
Digestive system | 1 | Gastroesophageal reflux |
Ears | 1 | Inner ear hearing loss (sensorineural hearing impairment) |
Pregnancy and birth | 1 | Decreased fetal movement |
3 |
30% |
Clinical study results | 2 | 20% |
Other research | 1 | 10% |
Disease patterns and progression | 1 | 10% |
Cuadros Gamboa AL (2026). [PMID: 41420984](https://pubmed.ncbi.nlm.nih.gov/41420984/). *Stem cell research*. [Basic Science / Preclinical]
Zárate-Segura PB (2025). [PMID: 39740904](https://pubmed.ncbi.nlm.nih.gov/39740904/). *In vivo (Athens, Greece)*. [Basic Science / Preclinical]
Dudoignon B (2025). [PMID: 40152101](https://pubmed.ncbi.nlm.nih.gov/40152101/). *Pediatric pulmonology*. [Clinical Trial Publication]
Guan Y (2025). [PMID: 41147225](https://pubmed.ncbi.nlm.nih.gov/41147225/). *Pediatric pulmonology*. [Case Report / Case Series]
Lee JY (2025). [PMID: 39543819](https://pubmed.ncbi.nlm.nih.gov/39543819/). *Bioethics*. [Other]
Omata K (2025). [PMID: 40130444](https://pubmed.ncbi.nlm.nih.gov/40130444/). *Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine*. [Basic Science / Preclinical]
Ingrisani M (2025). [PMID: 39900069](https://pubmed.ncbi.nlm.nih.gov/39900069/). *Medicina*. [Epidemiology / Natural History]
Monckeberg JE (2024). [PMID: 39219706](https://pubmed.ncbi.nlm.nih.gov/39219706/). *Journal of experimental orthopaedics*. [Clinical Trial Publication]
Dudoignon B (2024). [PMID: 38961480](https://pubmed.ncbi.nlm.nih.gov/38961480/). *Orphanet journal of rare diseases*. [Case Report / Case Series]
Malbos M (2024). [PMID: 38287449](https://pubmed.ncbi.nlm.nih.gov/38287449/). *Clinical genetics*. [Case Report / Case Series]