This is a multi-center, double-blind trial to assess the safety and efficacy of taliglucerase alfa in untreated subjects (2 to <18 years old) with Gaucher disease randomly assigned to treatment with one of two doses, 30 or 60 units/kg. Subjects will receive an intravenous (IV) infusion of taliglucerase alfa every two weeks. The total duration of treatment will be 12 months. At the end of the 12-month treatment period eligible subjects will be offered enrollment in an open-label extension study if taliglucerase alfa is not commercially available.

Inclusion Criteria:

• Males and females 2 to <18 years old.
• Diagnosis of Gaucher disease with leukocyte acid β-glucosidase activity ≤30% of the mean of the reference range for healthy subjects.
• Subjects who have not received enzyme replacement therapy (ERT) in the past or who have not received ERT in the past 12 months and have a negative anti-glucocerebrosidase antibody assay.
• Subjects who have not received substrate reduction therapy (SRT) in the past 12 months.
• Subjects whose clinical condition, in the opinion of the investigator, requires treatment with enzyme replacement therapy (ERT).

Exclusion Criteria:

• Currently taking another investigational drug for any condition.
• Presence of neurological signs and symptoms characteristic of Gaucher disease with complex neuronopathic features other than longstanding oculomotor gaze palsy.
• Presence of unresolved anemia due to iron, folic acid, or vitamin B12 deficiency
• Previous hypersensitivity reaction to Cerezyme® (imiglucerase) or Ceredase® (alglucerase).
• History of allergy to carrots.
• Presence of HIV, HBsAg or hepatitis C infections.
• Subject's parent(s) or legal guardian(s) are unable to understand the nature, scope and possible consequences of the study.
• Presence of any medical, emotional, behavioral or psychological condition that in the judgment of the Investigator would interfere with the subject's compliance with the requirements of the study.

1 year