The PEHO syndrome (progressive encephalopathy with oedema, hypsarrhythmia and optic atrophy)

The PEHO syndrome (progressive encephalopathy with oedema, hypsarrhythmia and optic atrophy) is an early onset neurodegenerative disorder presenting with infantile spasms, profound psychomotor retardation, hypotonia, and loss of visual contact. The patients have characteristic facial features and a typical deviation of gaze upwards or sidewards. In 16 out of 18 patients, considered to have the PEHO syndrome on the basis of neuropathological or neuro-radiological studies, atrophic optic discs with absent pupillary reactions to light and extinguished visual evoked potentials were noted after two years of age. Two patients whose radiographic findings suggested the PEHO syndrome did not develop optic atrophy; in these cases the diagnosis of the true PEHO syndrome remains questionable. A histological study of the eyes of three patients showed extremely attenuated nerve fibre and ganglion cell layers with loss of nerve fibres and myelin sheaths from the optic nerves.Sixteen other patients with a clinical suspicion of the PEHO syndrome but with different neuropathological or neuroradiological findings frequently showed pale optic discs suggesting the possibility of optic atrophy, but visual evoked potentials could be elicited in most of them. In two of these cases a histopathological examination of the eye was undertaken; in both cases the retina and the optic nerve were normal.