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ORPHA:2182

Hydrocephalus with stenosis of the aqueduct of Sylvius

medium confidenceSubtype of disorder

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

Publications

7,999

94.9th percentile

Trials

0

Interventional, condition-specific

Researchers

1,151

Distinct authors in sample

Gene link

L1CAM

Definitive

Readiness

4/6

Stages with a signal

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.

Orphanet entry

Cross-references

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

Additional Mondo synonyms (5)

X-linked hydrocephalus with stenosis of the aqueduct of Sylvius · hydrocephalus due to aqueductal stenosis, X-linked recessive · hydrocephalus with congenital idiopathic intestinal pseudoobstruction, X-linked recessive · hydrocephalus with hirschsprung disease, X-linked recessive · hydrocephalus with stenosis of the aqueduct of Sylvius

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.”

4/6 stages with a signal

No specific-condition interventional trial, but broader-category trials exist — discuss eligibility with a clinician.

  1. Gene identifiedPresent

    Definitive — L1CAM

  2. LiteraturePresent

    7,999 matched papers (5,473 in last 10 years) Source

  3. Phenotype characterisedPresent

    27 HPO annotations (e.g. Spasticity; Intellectual disability; Macrocephaly) Source

  4. Animal modelNot found

    No Alliance genotype “model of” associations via Monarch for these Mondo IDs

  5. Orphan designationNot found

    No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source

  6. Interventional trialPartial

    None under the specific name; 122 for broader category hydrocephalus

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 (L1CAM).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

27

Associated phenotypes · MONDO:0010611

  • Spasticity
  • Intellectual disability
  • Macrocephaly
  • Aqueductal stenosis
  • Hydrocephalus

Showing 5 of 27 — open Monarch for the full list.

Animal models (Monarch / Alliance)

None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.

Monarch fetch 2026-07-27

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)

No designation matched this disease via UMLS or preferred name on the FDA OOPD mirror or EMA orphan register. Absence here is not proof that none exists under another wording.

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?

7,999

7,999 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.

7,999 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).

5,473 in the last 10 years · medium confidence · 94.9th percentile (publications denominator)

Phrase hits: 420 · MeSH hits: 1

Open Europe PMC search

Who's working on it?

1,151

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

No interventional trial matched this name; these authors publish on it in the sampled literature — a practical starting point for contact.

  1. 01
    Yamasaki M10 papers · 2015

    Institute for Clinical Research, Osaka National Hospital, Osaka, Japan.

    Papers in Europe PMC
  2. 02
    Kanemura Y9 papers · 2022

    Tissue Engineering Research Center, National Institute of Advanced Industrial Science and Technology, Amagasaki, Hyogo, Japan.

    Papers in Europe PMC
  3. 03
    Saugier-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
  4. 04
    Kenwrick S5 papers · 1998

    University of Cambridge Department of Medicine, Addenbrooke's Hospital, UK.

    Papers in Europe PMC
  5. 05
    Okamoto N5 papers · 2006

    Department of Planning and Research, Osaka Medical Centre, Japan.

    Papers in Europe PMC
  6. 06
    Dobyns 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
  7. 07
    Drouot 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
  8. 08
    Jouet M4 papers · 1997

    Department of Medicine, University of Cambridge, UK.

    Papers in Europe PMC
  9. 09
    Lemmon 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
  10. 10
    Li 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

Clinical research

Is a treatment being tested?

0

interventional trials for this specific condition

No interventional trial testing a treatment matched this specific condition name. 1 observational study did — shown below because natural-history and cohort work can be an important step toward a trial. 122 trials are registered for hydrocephalus, the broader category — shown separately because they may or may not enrol this specific subtype.

Data as of 9 September 2026 · last trial check 9 September 2026

No matched interventional trials. This is true for 77.2% of diseases in the trials denominator (5501 of 7126). Here are the researchers publishing on it.

medium confidence · 38.6th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

No interventional trial testing a treatment was found for this specific condition name on ClinicalTrials.gov.

122 interventional trials matched hydrocephalus, the broader category — listed below. Those studies are not counted in the condition-specific total.

Broader category: hydrocephalus

122

Interventional trials for the parent category, exclusive of NCT IDs already counted above. Eligibility for this subtype is not guaranteed.

Worth raising with a clinician. How we count trials.

Recruiting under the broader category

Observational and natural-history studies

1 observational study matches 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 0 · after dedupe 0 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 0 · dropped 0 · fetched 2026-07-27

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).

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 Hydrocephalus with stenosis of the aqueduct of Sylvius — 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.

("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 (MESH:"Hydrocephalus, X-linked") OR ("L1CAM" OR "L1CAM syndrome" OR "L1CAM-related")

Run this search on Europe PMC

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"

Study-type breakdown: 0 interventional · 1 observational · 0 expanded access. Only interventional studies enter the trial headline.

Parent-category trials query:

"hydrocephalus"

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

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

Ingested 2026-07-26T02:05:09.054Z