A 6-year-old girl with idiopathic severe aplastic anemia underwent unrelated BMT from a 4/6 HLA-matched (mismatches in HLA-A and HLA-DRB1 loci) male donor after 2 courses of immunosuppressive therapy consisting of rabbit ATG and cyclosporin A in combination with eltrombopag. The gene discussed is HLA-DRB1; the disease is idiopathic aplastic anemia.