Notably, splicing dysregulation in L1CAM underlies the phenotypic spectrum of L1 syndrome - encompassing X-linked hydrocephalus with aqueductal stenosis (HSAS, OMIM #307000), MASA syndrome (OMIM #303350), SPG1, and corpus callosum agenesis (OMIM #304100) (Kenwrick et al., 1996; Vos et al., 2010). Here, L1CAM is linked to MASA syndrome.