Transient global amnesia triggered by migraine in monozygotic twins.

Transitory global amnesia and migraine without aura are diseases with unclear pathophysiologic mechanisms, but with evidence of comorbidity. We describe twin monozygotic brothers, both presenting episodes of transitory global amnesia occurring only during attacks of migraine without aura. This report supports the hypothesis of a common underlying pathogenetic mechanism, possibly related to the cortical spreading depression. Furthermore, a common genetic trait in both the diseases or more probably in a particular subgroup of patients could be hypothesized.