5.1. Association of migrainous occipital stroke with mtDNA haplogroup U (I)

Twenty-nine patients with an occipital stroke were assessed clinically and interviewed for a history of migraine. This was diagnosed in 18 patients (5 men, 13 women). Migraine was deemed to be a probable aetiology for stroke in five patients and a possible aetiology in one. The median age at stroke onset in these six patients was 29 years. Migraine with aura was present in four of these patients and three had a family history of migraine. Interestingly, an increased amount of fat or accumulations of subsarcolemmal or interfibrillar mitochondria were seen in electron microscopy of the muscle in three out of four patients with migraine-associated stroke examined in this way. The mtDNA mutations 3243A>G, 8344A>G, 8993T>G and 11778G>A, and also the common 4977 bp deletion were excluded in these patients.

All five patients with a probable migraine-associated stroke were found to belong to the mtDNA haplogroup U, whereas the patient with a possible migraine-associated stroke belonged to haplogroup V, thus suggesting a frequency of 83% for haplogroup U. This frequency differed significantly from that of 17% found among healthy controls in the same population, and from that of 25% found among the remaining 12 patients with migraine and unrelated stroke. Furthermore, the frequency of mtDNA haplogroup U was 19% among 42 patients who met the International Headache Society criteria for migraine but had not suffered a stroke. None of these patients harboured the 3243A>G mtDNA mutation.