At present, genome-wide association studies (GWAS) and other studies have preliminarily identified genes associated with Hashimoto’s thyroiditis (35–37), including genes that encode for thyrotropin receptor (TSHR), BACH2 (BACH2), FOXE1 (FOXE1), HLA class I molecules (HLA class I region), ribonuclease 2A (RNASET2), cytotoxic T lymphocyte-associated antigen 4 (CTLA4), protein tyrosine phosphatase non-receptor type 22 (PTPN22), and interleukin-2 receptor α chain (IL2RA). Here, CTLA4 is linked to Hashimoto thyroiditis.