The purpose of this research study is to determine whether partial irradiation of the liver and liver cell transplantation can provide help for patients with life-threatening liver-based metabolic diseases who are unlikely to survive without extensive medical therapy or transplant. The goal of this research study is to determine if liver cell transplants can be effective as an alternative to organ transplantation. At the present time, liver cell transplants are experimental and have been done in a limited number of human subjects.