The purpose of the ET3RA is to establish an experimental model of stem cell transplantation that accomplishes two equally important goals: 1) to devise a strategy of protection of the child’s brain from the ravages of certain genetic diseases and 2) to devise a simultaneous strategy of transplantation that avoids immune system rejection. In our first year of work, we have shown that we can reliably produce the stem cells that we want to transplant into the brains of experimental animals (mice). We have also bred sufficient numbers of mice for the transplant experiments and have started the immune system-based strategy of transplantation. This puts us in the proper position to begin the brain stem cell transplantation in year 2. Thus, we are on course to accomplishing our goals for this ET3RA and for eventual development of this strategy for the initiation of clinical trials.