Review Article

Metabolic Causes of Epileptic Encephalopathy

Table 6

Pyridoxine and pyridoxal-5′-phosphate-dependent Epilepsies.

Pyridoxine- or folinic-acid-dependent epilepsies (PDE)Pyridoxal-5′-phosphate (PLP-) dependent epilepsy

Deficient enzymeAntiquitin (ATQ)Pyridox(am)ine phosphate oxidase (PNPO)
Blood chemistryNormal, but hypoglycemia and lactic acidosis have been reportedHypoglycemia and lactic acidosis common
Vanillactic acid (Urine)AbsentPresent
Pipecolic acid (blood, CSF)Normal
AASA* (blood, urine, CSF)Normal
Neurotransmitter metabolites (CSF)(Possible) ↑ 3-Methoxytyrosine↑ L-DOPA, 3-Methoxytyrosine
Homovanillic acid, 5-Hydroxyindoleacetic acid
Clinical signsPostnatal refractory seizures, gastrointestinal symptoms, encephalopathy with hyperalertness, sleeplessnessFetal distress and in utero fetal seizures, postnatal refractory seizures and encephalopathy

 *AASA: alpha-aminoadipic semialdehyde. Adapted from Pearl [2].