SNPs that are present in other autoimmune diseases, such as rs6679677 near PTPN22, rs3184504 in SH2B3, and rs2517532 in HLA class I region, are linked to HT, while rs4915077 near VAV3 [20] and other SNPs such as rs7850258, rs965513, rs925489, and rs10759944, all located near FOXE1 in chromosome 9, exhibit genome-wide significance with primary HT [18]. The gene discussed is PTPN22; the disease is hematocrit.