• Number of Patients Surviving on Study [ Time Frame: at 100 days, 1 year, and 3 years post transplant ] [ Designated as safety issue: Yes ]
• Number of Patients Who Failed Engraftment. [ Time Frame: Day 42 Post Transplant ] [ Designated as safety issue: Yes ]
• Number of Patients With Grade III-IV Acute Graft-versus-host Disease (aGVHD). [ Time Frame: Day 100 Post Transplant ] [ Designated as safety issue: Yes ]

The purpose of this study is to determine the safety and engraftment of donor hematopoietic cells using this conditioning regimen in patients undergoing a hematopoietic (blood forming) cell transplant for Hurler syndrome, Maroteaux Lamy syndrome, Mannosidosis, or I-cell disease.

Prior to transplantation, subjects will receive Busulfan intravenously (IV) via the Hickman line four times daily for 4 days, Cyclophosphamide intravenously via the Hickman line once a day for 4 days, and Anti-Thymocyte Globulin IV via the Hickman line twice daily for three days before the transplant. These three drugs are being given to subjects to help the new marrow "take" and grow.

On the day of transplantation, the donor's hematopoietic cells will be transfused via central venous catheter.

After hematopoietic cell transplant, subjects will then receive two drugs, cyclosporin and either methylprednisolone or Mycophenolate Mofetil (MMF). Cyclosporin and methylprednisolone or MMF are given to help prevent the complication of graft-versus-host disease and to decrease the chance that the new donor cells will be rejected.

• Mucopolysaccharidosis I
• Mucopolysaccharidosis VI
• Mannosidosis
• Mucolipidosis Type II (I-cell Disease)

• Procedure: Stem Cell Transplant
• Drug: Busulfan, Cyclophosphamide, ATG

Inclusion Criteria:

• Patients with Mucopolysaccharidosis, type I (e.g., Hurler syndrome), Maroteaux-Lamy syndrome (MPS VI), Alpha Mannosidosis, or mucolipidosis type II (I-cell disease) who have an HLA-identical or mismatched (at 1 antigen) related marrow, PBSC, or cord blood donor.
• Patients with Mucopolysaccharidosis, type I, Maroteaux-Lamy syndrome (MPS VI), Alpha Mannosidosis, or mucolipidosis type II (I-cell disease) who have an HLA-identical or HLA-1 antigen mismatched unrelated marrow, PBSC, or HLA-0-2 antigen mismatched umbilical cord blood donor.
• Patients with MPS type I, Maroteaux Lamy Syndrome (MPS VI), or mucolipidosis type II (I-cell disease) will have a mental developmental index within two standard deviations of the normal mean, as best as can be determined using Bayley scales of infant development or other standardized testing, recognizing that these may be affected by speech and/or hearing impairment.
• Adequate organ function:
• Cardiac: ejection fraction >40%; no decompensated congestive heart failure or uncontrolled arrhythmia
• Renal: serum creatinine <2.0 mg/dl
• Hepatic: total bilirubin <3x Upper limits of normal transaminases < 5.0 x Upper limits of normal
• Signed consent.

Exclusion Criteria:

• Presence of major organ dysfunction (see above)
• Pregnancy
• Evidence of HIV infection or known HIV positive serology
• Patients or parents are psychologically incapable of undergoing BMT with associated strict isolation or documented history of medical non-compliance
• Patients >50 kg may be at risk for having cell doses below the goal of ≥ 10 x 106 CD 34 cells/kg and therefore will not be eligible to receive unrelated PBSCs.