Monarch Disease Ontology identifier MONDO_0012438 (pontocerebellar hypoplasia type 5) (PCH5) is a very rare severe form of PCH with prenatal onset and characterized by fetal onset of clonus or seizures-like activity persisting in infancy and microencephaly leading to early postnatal death. There is significant overlap both in phenotype and in genotype between pontocerebellar hypoplasia types 4 and 5. Also known as: PCH5, fetal-onset olivopontocerebellar hypoplasia.