Allogeneic Bone Marrow Transplant for Inherited Metabolic Disorders

Rationale: Chemotherapy administration before a donor stem cell transplant is necessary to stop the patient's immune system from rejecting the donor's stem cells. When healthy stem cells from a donor are infused into the patient, the donor white blood cells can provide the missing enzyme that causes the metabolic disease. Sometimes the transplanted cells from a donor can make an immune response against the body's normal cells. Giving a monoclonal antibody, alemtuzumab, before transplant and cyclosporine and mycophenolate mofetil before and after transplant may stop this from happening. This may be an effective treatment for inherited metabolic disorders. Purpose: The design of this study is to achieve donor cell engraftment in patients with standard-risk inherited metabolic diseases with limited peri-transplant morbidity and mortality. This will be achieved through the administration of the chemotherapy regimen described. The intention is to follow transplanted patient for years after transplant monitoring them for complications of their disease and assisting families with a multifaceted interdisciplinary approach.

Primary Objective: * To estimate the proportion of patients with donor derived engraftment at day 100 post transplant as defined by 80% or greater donor cells in the CD3 (T cell) fraction Secondary Objectives: * To determine the incidence and severity of graft-versus-host disease (GVHD) by day 100 * To determine the incidence of peri-transplant mortality (death by day 100) * To monitor donor cell chimerism at various time points following allogeneic transplantation with this transplant regimen as determined at day 28, 42, 100, 6 months and yearly for 5 years.