Several GWAS for AITD (HT or GD), hypothyroidism, positivity for anti-thyroid (anti-TPO or anti-Tg) antibodies, and thyroid function parameters (including TSH or fT4 levels), have been undertaken (Table 2) (133–135, 139–146, 148, 154, 155, 157–160). This evidence concerns the gene TPO and hematocrit.