Any pontocerebellar hypoplasia type 1 in which the cause of the disease is a mutation in the EXOSC8 gene. The disease is pontocerebellar hypoplasia, type 1C (MONDO_0014485). Also known as: EXOSC8 pontocerebellar hypoplasia type 1, pontocerebellar hypoplasia type 1 caused by mutation in EXOSC8.