ORPHA:2182
Hydrocephalus with stenosis of the aqueduct of Sylvius
Also known as: Bickers-Adams syndrome · HSAS · X-linked HSAS · X-linked acqueductal stenosis · X-linked hydrocephalus · X-linked hydrocephalus with stenosis of aqueduct of Sylvius
Clinical definition (Orphanet)
A , X-linked, clinical subtype of L1 syndrome characterized by severe hydrocephalus often of onset, adducted thumbs, spasticity (mostly evidenced by brisk tendon reflexes and extensor plantar responses) and moderate to severe . This subtype represents the severe end of the L1 syndrome spectrum and is associated with poor prognosis.
How rare: 1-9 / 100 000 — about one to nine people per hundred thousand.
Is anyone studying this?
420
420 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=183) is 38.
420 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 38 (publications denominator n=183).
128 in the last 10 years · medium confidence · 71th percentile (publications denominator)
Is a treatment being tested?
2
trials for this specific condition
2 interventional trials matched this specific condition name; 1 currently recruiting in our sample. 119 trials are registered for hydrocephalus, the broader category — shown separately because they may or may not enrol this specific subtype.
Data as of 26 July 2026
119
trials for hydrocephalus, the broader category this belongs to
Trials registered for a broader category may or may not enrol people with this specific subtype — eligibility criteria vary, and the trial record often doesn't say. Worth raising with a clinician. How we count trials.
2 interventional trials — more than 59.2% of diseases in the trials denominator have none at all (151 of 255; this disease is at the 74.7th percentile).
medium confidence · 74.7th percentile (trials denominator)
Do we know what causes it?
Yes — we know a specific gene responsible (L1CAM).
GenCC classification: Definitive.
Who's working on it?
1,151
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.
- 01Yamasaki M10 papers · 2015
Institute for Clinical Research, Osaka National Hospital, Osaka, Japan.
Papers in Europe PMC - 02Kanemura Y9 papers · 2022
Tissue Engineering Research Center, National Institute of Advanced Industrial Science and Technology, Amagasaki, Hyogo, Japan.
Papers in Europe PMC - 03Saugier-Veber P6 papers · 2026
Department of Genetics and Reference Center for Developmental Disorders, Normandy Center for Genomic and Personalized Medicine, Normandie Univ, UNIROUEN, Inserm U1245 and Rouen University Hospital, F 76000, Rouen, France.
Papers in Europe PMC - 04Kenwrick S5 papers · 1998
University of Cambridge Department of Medicine, Addenbrooke's Hospital, UK.
Papers in Europe PMC - 05Okamoto N5 papers · 2006
Department of Planning and Research, Osaka Medical Centre, Japan.
Papers in Europe PMC - 06Dobyns WB4 papers · 2016
Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, WA, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA.
Papers in Europe PMC - 07Drouot N4 papers · 2026
Univ Rouen Normandie, INSERM U1245 and CHU Rouen, Department of Genetics and Reference Center for Developmental Disorders, 76000 Rouen, France.
Papers in Europe PMC - 08
- 09Lemmon VP4 papers · 2021
The Miami Project to Cure Paralysis, University of Miami School of Medicine, Lois Pope LIFE Center, Miami, Florida, United States of America.
Papers in Europe PMC - 10Li J4 papers · 2025
St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065.
Papers in Europe PMC
Recruiting interventional trials
Trials testing a treatment from the matched ClinicalTrials.gov set
2 interventional trials matched after quoted-phrase search and title/condition post-filter.
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.
Recruiting or not-yet-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 below but are not added to the query string.
"Hydrocephalus with stenosis of the aqueduct of Sylvius" OR "Bickers-Adams syndrome" OR "X-linked HSAS" OR "X-linked acqueductal stenosis" OR "X-linked hydrocephalus" OR "X-linked hydrocephalus with stenosis of aqueduct of Sylvius" OR "X-linked hydrocephalus with stenosis of the aqueduct of Sylvius" OR "hydrocephalus due to aqueductal stenosis, X-linked recessive" OR "hydrocephalus with congenital idiopathic intestinal pseudoobstruction, X-linked recessive" OR "hydrocephalus with hirschsprung disease, X-linked recessive"
MeSH descriptor terms unioned into the query: Hydrocephalus, X-linked
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Hydrocephalus with stenosis of the aqueduct of Sylvius" OR "Hydrocephalus with stenosis of aqueduct of Sylvius" OR "Bickers-Adams syndrome" OR "X-linked HSAS" OR "X-linked acqueductal stenosis" OR "X-linked hydrocephalus" OR "X-linked hydrocephalus with stenosis of aqueduct of Sylvius" OR "X-linked hydrocephalus with stenosis of the aqueduct of the Sylvius" OR "X-linked hydrocephalus with stenosis of the aqueduct of Sylvius" OR "hydrocephalus due to aqueductal stenosis, X-linked recessive" OR "hydrocephalus with congenital idiopathic intestinal pseudoobstruction, X-linked recessive" OR "hydrocephalus with hirschsprung disease, X-linked recessive" OR "Hydrocephalus, X-linked" OR "L1CAM" OR "congenital hydrocephalus"
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: 2 interventional · 2 observational · 0 expanded access. Only interventional studies enter the trial headline.
Cross-references (from Mondo): MESH:C536078 OMIM:307000 UMLS:C0265216
Query health: ok — strategies attempted: phrase, mesh, recall-expansion; with hits: phrase, mesh, recall-expansion
Run this search on ClinicalTrials.gov
Synonyms dropped by stoplist: HSAS
Confidence reasoning
- Preferred label is multi-word and distinctive
- 1 synonym(s) dropped by stoplist (may under-count)
- No label/synonym collisions with other diseases in this corpus