INPP5E and Joubert syndrome: INPP5E is mutated in Joubert syndrome (JS) (Bielas et al., 2009; Jacoby et al., 2009), a ciliopathy characterized by cerebellar defects in which a subset of patients also shows malformations of the cerebral cortex including heterotopias, polymicrogyria and agenesis of the corpus callosum (Valente et al., 2014).