Hyperthyroidism and the related thyroidtoxicosis are are not automimmune diseases, that is, the body attacking itself. The body is attacking the trapped toxins, metabolic waste, suffocated and degenerated cells, stagnating lymphatic components, etc. That this casues a major immune reaction and swelling is quite obvious. Genetic can play a role, but are not primary factors, as many people who have the genes for Graves Disease never get the disease.
When you take a look at the enlarged belly of people with Graves you can see the severe lymph edema in the lymphatic sacks (illustrated in The Amazing Liver Cleanse book). The congestion there is the main reason for Graves to occur. Liver and digestive problems, dietary and lifestyle factors are behind that occurrence. All major organs, liver colon, kidneys must be thoroughly cleansed, and diet be most likely Kapha-reducing (See The Key to Health and Rejuvenation).