Somer listed diagnostic criteria for the PEHO syndrome (Progressive Encephalopathy with Oedema, Hypsarrhythmia, and Optic Atrophy). The author is from the University of Helsinki in Finland.

Necessary criteria:

(1) infantile hypotonia, usually with neonatal onset

(2) convulsive disorder manifesting with myoclonic jerking and infantile spasms

(3) profound psychomotor retardation with severe hypotonia

(4) absence of motor milestones and speech

(5) absence or early loss of visual fixation with atrophy of optic discs by 2 years of age with normal electroretinogram and extinguished visual evoked potentials

(6) progressive brain atrophy in neuroimaging studies particularly in the cerebellum and brain stem; milder supratentorial atrophy


Supportive criteria:

(1) subtle dysmorphic features with narrow forehead, epicanthic folds, short nose, open mouth, receding chin, and tapering fingers

(2) edema of the face and limbs, especially in early childhood

(3) brisk tendon reflexes in early childhood

(4) abnormal brain stem and auditory evoked potentials

(5) absent cortical responses of somatosensory evoked potentials

(6) slow nerve conduction velocities in late childhood

(7) dysmyelination in magnetic resonance imaging (MRI)


Findings that are usually absent in PEHO syndrome:

(1) microcephaly present at birth

(2) abnormal gyral formation in neuroradiological studies

(3) predominating spasticity in infancy

(4) reappearance of visual contact after cessation of infantile spasms

(5) storage disorder and/or hepatosplenomegaly

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