There are accumulating evidences to suggest the role of CTLA4 variants to autoimmune diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Graves' disease, Hashimoto's thyroiditis, postpartum thyroiditis, Addison's disease, insulin-dependent diabetes mellitus, vitiligo and multiple sclerosis [28]–[36]. Here, CTLA4 is linked to Hashimoto thyroiditis.