Conditioning Regimen, Transplant, Graft and Donor Characteristics
Transplant characteristics are shown in Table 2. Patients 1 and 2 underwent busulfan-based myeloablative preparative regimens. Patients 3-6 had a treosulfan-based reduced intensity conditioning regimen. All patients were transplanted from a fully 10/10 HLA-matched related donor, including three siblings (patients 2, 5 and 6), one mother (patient 1) and two close family members (patients 3 and 4). The donors for four patients (patients 1, 2, 5 and 6) were heterozygous carriers of theTYMP mutation; the donor for patient 4 was wild type and in patient 3, unknown carrier status of donor..
Only patient 1 received peripheral blood stem cells collected from her matched mother, while all other patients were transplanted using bone marrow as the source of stem cells. Median total nucleated cell dose was 7.58 x108/kg (range 4.2-13.9) and median CD34+ dose was 6.98 x106/kg (range 3.0-12.4). All had graft versus host disease (GVHD) prophylaxis with cyclosporine and 3 doses of methotrexate.