Table 1

Clinical criteria for the diagnosis of PEHO syndrome as described by Somer3

Necessary criteriaSupportive criteriaFeatures that argue against the PEHO syndrome
Infantile, usually neonatal hypotoniaSubtle dysmorphic features with narrow forehead, epicanthic folds, short nose, open mouth, receding chin, tapering fingersMicrocephaly at birth
Convulsive disorder manifesting with myoclonic seizures and infantile spasmsOedema of the face and limbs, especially in early childhoodAbnormal gyral formation in neuroradiological studies
Profound psychomotor retardation with severe hypotonia; absence of motor milestones and speechBrisk tendon reflexes in early childhoodPredominating spasticity in infancy
Absence or early loss of visual fixation with atrophy of optic discs by 2 years; normal electroretinogram, extinguished visual evoked potentialsAbnormal brainstem auditory evoked potentialsReappearance of visual contact after cessation of infantile spasms
Progressive brain atrophy in neuroimaging studies, particularly in the cerebellum and brainstem; milder supratentorial atrophyAbsent cortical responses of somatosensory evoked potentialsHepato/splenomegaly or storage disorder in histological studies
Slow nerve conduction velocities in late childhood
Dysmyelination on MRI
  • PEHO,┬áprogressive encephalopathy, hypsarrhythmia and optic atrophy.