Search for a rare disease

* (*) mandatory field

Other search option(s)

Suggest an update

(*) Required fields.


Only comments seeking to improve the quality and accuracy of information on the Orphanet website are accepted. For all other comments, please send your remarks via contact us. Only comments written in English can be processed.

Orphanet doesn't provide personalised answers. To get in touch with the Orphanet team, please contact

Information provided in your contribution (including your email address) will be stocked in .CSV files that will be sent as an email to Orphanet's teams. These emails might be conserved in the teams' mailboxes, in our backoffice servers but will not be registered in our databases (for more information see our section General Data Protection Regulation and data privacy (GDPR) and Confidentiality).

Captcha image

Hydrocephalus with stenosis of the aqueduct of Sylvius

Disease definition

A congenital, X-linked, clinical subtype of L1 syndrome characterized by severe hydrocephalus often of prenatal onset, adducted thumbs, spasticity (mostly evidenced by brisk tendon reflexes and extensor plantar responses) and moderate to severe intellectual disability. This subtype represents the severe end of the L1 syndrome spectrum and is associated with poor prognosis.


Classification level: Subtype of disorder
  • Synonym(s):
    • Bickers-Adams syndrome
    • HSAS
    • X-linked HSAS
    • X-linked acqueductal stenosis
    • X-linked hydrocephalus
    • X-linked hydrocephalus with stenosis of aqueduct of Sylvius
  • Prevalence: 1-9 / 100 000
  • Inheritance: X-linked recessive 
  • Age of onset: Antenatal, Neonatal
  • ICD-10: Q03.0
  • ICD-11: LA04.0
  • OMIM: 307000
  • UMLS: C0265216
  • MeSH: C536078
  • GARD: 434
  • MedDRA: -

Detailed information

Disease review articles

ERN produced/endorsed by ERN(s)   FSMR produced/endorsed by FSMR(s)
The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care by a qualified specialist and should not be used as a basis for diagnosis or treatment.