1.2.3.1.2 Familial hemiplegic migraine type 2 (FHM2)

A 46-year-old head chef reports four attacks in total of a distinctive neurological syndrome over the last three years. Each episode begins with shimmering lights zig-zagging across his vision, a positive phenomenon he describes vividly rather than any blank patch, before his speech starts to slur and he cannot get words out properly, and finally a distinct weakness develops in one arm. Throughout every attack, the symptoms stay entirely on the right side of his body. A severe, pounding headache follows within an hour of the weakness coming on. His younger brother had specialist assessment some years ago and was confirmed to satisfy the recognised specialist criteria for the same inherited disorder, having an identical pattern of attacks with weakness himself. Given this family history, genetic testing was arranged and confirmed a disease-causing variant in the ATP1A2 gene.