Bone marrow transplantation for the treatment of genetic diseases.

Consideration of a bone marrow transplant (BMT) for a child with a genetic disease depends upon many factors including the pathophysiology of the disorder, the natural history of the disease, whether an alternative therapy exists and whether a donor is available. Children with disorders such as severe combined immunodeficiency disease (SCID), in which life expectancy is minimal, are obviously candidates for a BMT, even with less than optimal donors, while those with disorders such as beta-thalassemia major, in which an alternative therapy exists, must be considered more carefully and only with an optimal donor. The risks of conditioning therapy, graft-versus-host disease (GVHD), and early death as well as the cost are critical to this decision and must be viewed in light of the potential outcome of a successful BMT and the life expectancy and quality of life with a BMT. For some genetic diseases with multisystem involvement (e.g., Hurler's mucopolysaccharidosis), the efficacy of a BMT has been reasonably demonstrated, providing significant brain damage has not occurred previously. For some other storage-related diseases, there is no place for BMT. Further studies are essential to increase our knowledge as to its potential role in other types of genetic-associated diseases.