Familial hemiplegic migraine with a PRRT2 mutation: Phenotypic variations and carbamazepine efficacy

Objective: To understand the clinical characteristics of familial hemiplegic migraine (FHM) caused by a PRRT2 mutation and to examine the efficacy of preventive treatment. Methods: Using the literature, we investigated clinical details of FHM in 3 generations of patients with a PRRT2 mutation and compared them with those in 17 patients with the same mutation from 6 families. Results: In most of the affected patients, the onset was observed during the teen years. Complicated phenotypes tended to be shared in each family, and five patients showed spontaneous remission. With regard to treatment, low-dose carbamazepine (CBZ) was effective in three patients. Conclusion: Considering the clinical features, we suggest that low-dose CBZ is efficacious for FHM treatment in patients with a PRRT2 mutation. The treatment duration should be carefully considered because some patients show spontaneous remission. More accumulated data from familial cases might help elucidate PRRT2 function and establish standard treatment for FHM.