Type 1 Gaucher disease, the most common form, accounts for more than 90% of all cases of Gaucher disease and does not involve the CNS. Typical manifestations of type 1 Gaucher disease include hepatomegaly, splenomegaly, thrombocytopenia, bleeding tendencies, anemia, hypermetabolism, skeletal pathology, growth retardation, pulmonary disease, and decreased quality of life. Velaglucerase alfa (Gene-Activated™ human glucocerebrosidase;GA-GCB) is produced in a continuous human cell line using proprietary gene-activation technology and has an identical amino acid sequence to the naturally occurring human enzyme. Velaglucerase alfa contains terminal mannose residues that target the enzyme to the macrophages-the primary target cells in Gaucher disease. This treatment protocol will observe the safety of velaglucerase alfa in patients with type 1 Gaucher disease who are either treatment naive (newly diagnosed) or who are currently being treated with the Enzyme Replacement Therapy (ERT) imiglucerase. Patients currently being treated with ERT for their Gaucher disease will receive the same number of units of velaglucerase alfa per month as their imiglucerase dose for doses between 30-120 U/kg/month. For patients who experienced dose reductions in their imiglucerase treatment due to supply constraints the pre-reduction monthly dose may be used to determine the monthly dose of velaglucerase alfa.