A case of MELAS syndrome with typical cluster headache attacks: Is it a causal or coincindental association?

Many findings relate migraine and cluster headaches to a genetic alteration, even if the site of the defect has not been identified. Some of these findings indicate an involvement of mitochondrial DNA, although some contrasting results have been reported. We describe a case of cluster headache occurring in a patient with MELAS syndrome. The diagnosis of MELAS was supported by the familiar anamnesis (the mother suffered from a similar form), by the laboratory reports (lacto-acidosis), by instrumental analysis (signs of encephalopathy on magnetic resonance imaging) and by biopsy findings (myopathy). The diagnosis was confirmed when a point mutation (Leu mutation at position 3423 of mitochondrial RNA) was found in the mitochondrial gene. The recurrent periods, characterized by attacks of unilateral pain and accompanied by homolateral symptoms (e.g. tearing, palpebral ptosis, rhinorrea), did not leave any doubt as to the diagnosis of cluster headache. We discuss whether the co-existence of MELAS and cluster headache was coincidental or causal.