IN THIS ISSUE of the ARCHIVES, Kors et al1 describe the clinical features of patients with familial hemiplegic migraine (FHM) in 5 unrelated families. They point out that a threonine-to-methionine substitution at position 666 in the polypeptide chain of the α1-subunit of the neuronal calcium channel (T666M) is the most frequent mutation in autosomal dominant FHM. All neurologists know that migraine symptoms range from mild to severe and that a family history of similar headaches is very common. The reader would assume that a well-defined mutation should convey identical clinical manifestations. Kors and colleagues show that this assumption is incorrect. In addition to migraine and hemiplegia, their patients had 1 or more of the following: confusion, coma, progressive cognitive decline, aggressive behavior, aphasia, ataxia, anisocoria, fever, and spinal fluid pleocytosis. Imaging studies showed a frank, ultimately fatal cerebral infarction in one patient and cerebellar atrophy in another. Cerebral angiography caused prolonged coma and high fever in a third patient, highlighting the sensitivity of the migrainous cerebral vasculature to angiographic contrast and the general prohibition of this radiographic test. Acetazolamide was only modestly effective. Interestingly, a 24-year-old woman with the T666M mutation had never had an attack of migraine.
Koeppen AH. Familial Hemiplegic Migraine. Arch Neurol. 2003;60(5):663-664. doi:10.1001/archneur.60.5.663