label: X-linked hydrocephalus with stenosis of the aqueduct of Sylvius
label_lc: x-linked hydrocephalus with stenosis of the aqueduct of sylvius
description: A form of L1 syndrome caused by changes in the L1CAM gene characterized by severe hydrocephalus mostly with prenatal onset, signs of intracranial hypertension, adducted thumbs, spasticity, and severe intellectual deficit. HSAS represents the severe end of the spectrum and is associated with poor prognosis.