PEHO syndrome (MONDO_0009841) is pEHO (Progressive encephalopathy with Edema, Hypsarrhythmia and Optic atrophy) syndrome is a rare neurodegenerative disorder belonging to the group of infantile progressive encephalopathies. Also known as: peho syndrome, progressive encephalopathy with edema, hypsarrhythmia and optic atrophy, progressive encephalopathy-optic atrophy syndrome.