Pilot and Feasibility Study of Hematopoietic Stem Cell Gene Transfer for the Wiskott-Aldrich Syndrome

The Wiskott-Aldrich Syndrome (WAS) is an inherited disorder that results in defects of the blood and bone marrow. It affects boys because the genetic mistake is carried on the X chromosome. Normal people have blood cells called platelets that stop bleeding when blood vessels are damaged. Boys with WAS have low numbers of platelets that do not function correctly. Boys with WAS are thus at risk for severe life-threatening bleeding. A normal immune system is made of special blood cells called white blood cells, which protect against infection and also fight certain types of cancer. In WAS, these white blood cells don't work as well as they should, making these boys very susceptible to infections and to a form of blood cancer known as lymphoma. The abnormal white blood cells of patients with WAS also cause diseases such as eczema and arthritis. Although WAS can be mild, severe forms need treatment as early as possible to prevent life-threatening complications due to bleeding, infection and blood cancer. Over the past decade, investigators have developed new treatments based on the investigators knowledge of the defective gene causing WAS. The investigators can now use genes as a type of medicine that will correct the problem in the patient's own bone marrow. The investigators call this process gene transfer. The procedure is very similar to a normal bone marrow transplant, in that the old marrow is killed off using chemotherapy, but is different because the patient's own bone marrow is given back after it is treated by gene transfer. This approach can be used even if the patient does not have any matched donors available and will avoid problems such as GVHD and rejection. The investigators wish to test whether this approach is safe and whether gene transfer will lead to the development of a healthy immune and blood system.