Landau-Kleffner syndrome with mitochondrial respiratory chain-complex I deficiency.

Landau-Kleffner syndrome is characterized by epileptic aphasia associated with electrical status epilepticus of slow wave sleep. A 5-year-old female, who had manifested normal developmental progress, was referred with principal complaints of fluctuating sensory aphasia and bizarre behavior during the preceding 4 months. Landau-Kleffner syndrome was confirmed by clinical and electroencephalographic features; in addition, the patient's mitochondrial respiratory chain-complex I deficiency was confirmed by fibroblast culture with the evidence of energy metabolism disorder. This patient's seizures were intractable to many antiepileptic drugs, adrenocorticotrophic hormone, and intravenous immunoglobulin, with catastrophic cognitive and behavioral decline, but the seizures were successfully controlled by ketogenic diet with supplementary mitochondrial cocktail including coenzyme Q10, riboflavin, L-carnitine, and high-dose multivitamins. The patient finally regained fully normal cognitive functioning. Landau-Kleffner syndrome with mitochondrial respiratory chain-complex I deficiency was controlled in this case by ketogenic diet and supplementary mitochondrial cocktail therapy.