[Mitochondrial disorder underlying headache symptoms].

MERRF (myoclonic epilepsy with ragged red fibers) is a rare mitochondrial disorder affecting the function of several distinct organs. Diagnosis of the syndrome has conventionally been made on the basis of the patient's myoclonic epilepsy and the so-called ragged red fibers observed in the patient's muscle biopsy. The diagnosis is confirmed by mutation analysis. Symptoms and findings vary from patient to patient even within one family. A strain-associated headache episode and bout of nausea with deficiency symptoms occurs as the most severe symptom in the young boy of our case report.