pontocerebellar hypoplasia type 3 (Monarch Disease Ontology identifier MONDO_0011948) (PCH3), also known as cerebellar atrophy with progressive microcephaly (CLAM) is a rare form of pontocerebellar hypoplasia with autosomal recessive transmission characterized neonatally by hypotonia and impaired swallowing and from infancy onward by seizures, optic atrophy and short stature, but none of the clinical findings are specific for PCH3. Also known as: PCH with optic atrophy, PCH without dyskinesia, PCH3, PCLO non-syndromic pontocerebellar hypoplasia, cerebellar atrophy with progressive microcephaly, clam, non-syndromic pontocerebellar hypoplasia caused by mutation in PCLO.