On the other hand, a study on 625 white Caucasian HT patients from the UK showed a predisposing effect for HT detected at -DRB1*03 [55], while research performed on 235 patients with AITD in south India found the protective effects of the -DRB1*03 allele group against HT [56]. The gene discussed is HLA-DRB1; the disease is hematocrit.