Familial hemiplegic migraine (FHM) is a rare autosomal dominant neurological disorder linked to mutations in several genes, including CACNA1A, ATP1A2, SCN1A, and PRRT2. It is characterized by reversible motor weakness that often leads to its misdiagnosis as a stroke or transient ischemic attack (TIA). The gene discussed is ATP1A2; the disease is familial hemiplegic migraine.