Pontocerebellar hypoplasia type 2 (PCH2) is the most common subtype of pontocerebellar hypoplasia characterized by neonatal onset and a lack of voluntary motor development and later progressive microencephaly, generalized clonus, development of chorea and spasticity. The majority of patients will not reach puberty. The disease is pontocerebellar hypoplasia type 2 (Monarch Disease Ontology id MONDO_0016759). Also known as: PCH2.