The purpose of this clinical study is to evaluate the biochemical and therapeutic effects and safety of enzyme replacement therapy using polyethyleneglycol (PEG) modified glucocerebrosidase for the treatment of Gaucher disease and to evaluate the benefit to risk ratio. The study is designed to determine the safety and efficacy in Gaucher patients of recombinantly produced human glucocerebrosidase, which is PEG modified. Parameters to be monitored include hemoglobin, platelet counts, organ size, and extent of bony involvement. Pharmacokinetic, pharmacodynamic, and antibody studies will also be evaluated.