Cord Blood Transplant in Children and Young Adults With Blood Cancers and Non-malignant Disorders

Participant Inclusion Criteria: Age and Donor Status: Patients with age ≤ 21 years at time of consent with no available and suitably matched related or unrelated donor in the required time period. Diagnoses : I. Acute myelogenous leukemia (AML) : * Complete first remission (CR1) at high risk for relapse such as any of the following: * Known prior diagnosis of myelodysplasia (MDS) or myeloproliferative disorder (MPS). * Therapy-related AML (t-AML). * White cell count at presentation \> 100,000. * Presence of extramedullary leukemia at diagnosis. * Any unfavorable subtype by FAB or WHO classification. * High-risk cytogenetics (e.g. those associated with MDS, abnormalities of 5, 7, 8, complex karyotype) or high-risk molecular abnormalities. * Requirement for 2 or more inductions to achieve CR1. * Presence of Minimal Residual Disease (MRD+) by cytogenetics, flow cytometry or molecular methods after induction. * Any patient with newly diagnosed AML with intermediate risk cytogenetics who elects allograft with curative intent over consolidation chemotherapy. * Any patient unable to tolerate consolidation chemotherapy as would have been deemed appropriate by the treating physician. * Other high-risk features not defined above. * Complete second remission (CR2). * Primary refractory or relapsed AML with less than 10% blasts by bone marrow morphology. Patients with cytogenetic, flow cytometric, or molecular abnormalities in ≤ 10% of cells are eligible. II.…