Genetic diagnosis and acetazolamide treatment of familial hemiplegic migraine.

A female patient presented with horizontal gaze nystagmus, mild cerebellar ataxia, recurrent headache and hemiplegia since childhood with cerebellar atrophy on magnetic resonance imaging. Genetic analysis revealed a CACNA1A gene mutation, leading to a diagnosis of familial hemiplegic migraine (FHM1). FHM is very rare, but should be considered as a differential diagnosis for childhood cerebellar symptoms and/or cerebellar atrophy. To avoid missing FHM1, a detailed clinical history including headache or hemiplegia is essential. Oral acetazolamide during the aura phase, comprising mild headache and abnormal leg sensation, relieved these symptoms in this patient, suggesting that acetazolamide could represent a first line of treatment.