Table 2

- Main clinical, EEG, and MRI findings suggesting inherited metabolic epilepsies.

OnsetEarly: neonatal, infancy or early childhood
Seizure typesMyoclonic, tonic, infantile spasms
Seizures worsening with fasting (GLUT1) or with high protein meals (urea cycle defects)
Progressive myoclonic epilepsy phenotype
Seizures refractory to anti-epileptic drugs
Seizures worsening with anti-epileptic drugs
Neurological featuresDevelopmental delay /regression
Movement disorders
Fluctuating course of illness
Systemic symptomsDysmorphic features
Ophthalmological abnormalities (cataracts, retinitis pigmentosa,cherry red spot, optic nerve atrophy)
Family historyParental consanguinity
Metabolic or unexplained neurological disorder
Death of unknown etiology
EEGBurst-suppression, multifocal spike discharges, hypsarrhythmia Comb-like rhythm (maple syrup urine disease)
MRI/MRSNormal / non specific abnormalities
Corpus callosum dysgenesis (pyruvate dehydrogenase deficiency)
Abnormal MRS in cerebral creatine deficiency or GABA transaminase deficiency