L1 syndrome https://github.com/monarch-initiative/mondo/issues/5588 corpus callosum hypoplasia-retardation-adducted thumbs-spasticity-hydrocephalus syndrome MONDO:0017140 L1 syndrome is a mild to severe congenital X-linked developmental disorder characterized by hydrocephalus of varying degrees of severity, intellectual deficit, spasticity of the legs, and adducted thumbs. The syndrome represents a spectrum of disorders including: X-linked hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS), MASA syndrome, X-linked complicated hereditary spastic paraplegia type 1, and X-linked complicated corpus callosum agenesis. MEDGEN:1830362 CRASH syndrome L1 syndrome UMLS:C5779710 NORD:1343 GARD:0012524 icd11.foundation:1457804873 Orphanet:275543 L1CAM syndrome X-linked syndromic intellectual disability disorder of development or morphogenesis