Monarch Disease Ontology term MONDO_0008939 (isolated cerebellar hypoplasia/agenesis) can be described as follows. Hypoplasia of the cerebellum that is associated with inherited metabolic disorders and neurodegenerative disorders. Signs and symptoms include mental and developmental delays, walking and balance difficulties, floppy muscle tone, and seizures. Also known as: Cerebellar Agenesis, Chiari 4 malformation, Chiari IV malformation, cerebellar hypoplasia/atrophy, epilepsy, and global developmental delay, congenital cerebellar Hypoplasia, near total absence of cerebellum, subtotal absence of cerebellum.