CTLA4 and autoimmune thyroid disease: Autoimmune thyroid disease including Graves’ disease, which accounts for 95% of pediatric hyperthyroidism [1], is associated with several single nucleotide polymorphisms in immune-regulating genes including FOXP3, CD25,CD40, CTLA-4, the HLA genes, and PTPN22, which may be the case for our patient since her sister is also affected [8].