MONDO_0012683 (pontocerebellar hypoplasia type 6) (PCH6) is a rare form of pontocerebellar hypoplasia characterized clinically at birth by hypotonia, clonus, epilepsy impaired swallowing and from infancy by progressive microencephaly, spasticity and lactic acidosis. Also known as: PCH6, RARS2 non-syndromic pontocerebellar hypoplasia, fatal infantile encephalopathy with mitochondrial respiratory chain defects, non-syndromic pontocerebellar hypoplasia caused by mutation in RARS2.