Joubert syndrome (JS) is characterized by congenital malformation of the brainstem and agenesis or hypoplasia of the cerebellar vermis leading to an abnormal respiratory pattern, nystagmus, hypotonia, ataxia, and delay in achieving motor milestones. The disease is Monarch Disease Ontology identifier MONDO_0018772 (Joubert syndrome). Also known as: CPD IV, JBTS, Joubert syndrome type A, Joubert-Boltshauser syndrome, cerebelloparenchymal disorder IV, classic Joubert syndrome, pure Joubert syndrome.