Osteodysplasia or poorly formed bones, "brittle bones" is a genetic disease with no known proven treatments. Some forms of osteodysplasia may cause severe disability and even death.

Eligible patients were limited to those children with Osteodysplasia who had undergone a previous allogeneic bone marrow transplant at St. Jude. The study intervention involved an infusion of a specified number of ex vivo expanded stromal cells obtained from the bone marrow of the same donor from whom they received their primary transplant procedure. These bone marrow stromal cells can become bone-forming cells, called osteoblasts. Participants then received 2 infusions of ex vivo expanded, gene marked cells not less than 6 months after bone marrow transplantation. The second cell infusion occurred between 14 to 21 days after the first infusion in the absence of toxicity. The goal of the study was to evaluate the safety and toxicity of these infusions.

• To determine whether these ex vivo expanded, gene marked marrow stromal cells will engraft in the recipient's bone, bone marrow, and/or skin.
• To begin to investigate whether high proliferative mesenchymal progenitor cells can be expanded ex vivo and retain their progenitor potential in vivo.
• To begin to investigate whether ex vivo expanded bone marrow stromal cells can ameliorate the skeletal dysplasias associated with various genetic disorders.

Inclusion Criteria:

• Patients with an appropriate genetic disorder who have had an allogeneic bone marrow transplant and currently maintain complete or mixed hematopoietic chimerism
• Patient must be < or equal to 18Kg

Exclusion Criteria:

• Presence of infection
• Presence of GVHD (graft versus host disease)or the need for prophylaxis
• Concurrent participation in any investigational study that could potentially confound the interpretation of the safety parameters being investigated in this study.