Gene mutations in membrane ion channel transport proteins, including CACNA1A (P/Q-type voltage-gated calcium channel), ATP1A2 (sodium-potassium ATPase), SCN1A (voltage-gated sodium channel), and PRRT2 (proline-rich transmembrane protein 2) lead to FHM. The gene discussed is PRRT2; the disease is familial hemiplegic migraine.