Skeletal response over 4 years of Cerezyme therapy

Assess use of skeletal parameter as indicative of treatment response and use in dose management

Signed informed consent.
Confirmed diagnosis of Type I Gaucher disease, with no prior enzyme replacement therapy, gene therapy or bone marrow transplantation, and who are ambulatory.
Age 10-65 (patients 66-70 years of age are considered on a case-by-case basis following careful medical review).
Dual energy X-ray absorptiometry (DEXA) of the femoral nech with a T-score = -1.0.
One of more of the following signs as documented by X-ray, computed tomography (CT), or magnetic resonance imaging (MRI), or symptoms of bone disease as documented in the patient’s medical history or baseline examinations: a). history of at least one bone crises; b). Erlenmeyer flask deformity of the femora in children (10-17 years old); c). osteoarticular necrosis; d). medullary infarctions; e). lytic lesions; f). pathological fractures or fractures related to Gaucher disease; g). marrow infiltration to a degree such that Rosenthal’s Magnetic Resonance Score was = 3; h). bone density by quantitative computed tomography (QCT) or DEXA = 1.5 standard deviation (SD) below age-adjusted normal value; and i). fat fraction = 17%.

More than 1 joint replacement (revision surgery such as repair or replacement of a previously replaced joint is allowed).
Pregnant, lactating or per-menopausal women.
Active, uncontrolled infection, such as hepatitis B, hepatitis C or human immunodeficiency virus (HIV).
Major concurrent disorders (i.e. cancer, renal disease) or disorders known to affect bone (e.g. uncontrolled thyroid disease, hyperparathyroidism, hypoparathyroidism, gastrectomy, malabsorption, inflammatory bowel disease, rheumatoid arthritis, ankylosing spondylitis).
Medications known to affect bone homeostasis (e.g. chronic oral corticosteroids, anticonvulsants, phenytoin and phenobarbital, hyper-physiological doses of estrogen, defined as > 0.625mg, or androgens, bisphosphates, calcitonin) within the first 2 months of the first Cerezyme infusion.
Emotional, behavioral or psychological problems, which in the judgment of the principal investigator, would interfere with the patient adequately complying with the requirement of the study.