Bone Abstracts

Introduction: Gaucher disease (GD), the most prevalent glycolipid storage disease, is an autosomal recessive metabolic disorder that is caused by an inherited deficiency of the lysosomal enzyme, glycocerebrosidase. This defect leads to reduce enzyme activity, resulting in the accumulation of glucosylceramide in cells of the monocyte-macrophages linage, known as Gaucher cells. Common presenting features include anemia, thrombocytopenia, hepatosplenomegaly and bone abnormalities. Skeletal disorders include osteopenia, bone pain crisis, bone infarctions, avascular bone necrosis (of the proximal and distal end of femur, proximal end of tibia and humerus), osteolytic lesions and fractures. Currently enzyme replacement therapy (ERT) has demonstrated a fast recovery of the cytopenias and visceromegalies. Besides, it has shown beneficial effects in both bone pain and the development of osteoporosis.

Objectives: The objective of this work was to analyze the clinical characteristics and bone involvement of GD patients diagnosed and controlled in our department.

Methods: Descriptive study including GD patients diagnosed in our department. In all patients we analyzed clinical and laboratory data (including PTH, 25OHD, P1NP and βCTX); bone mineral density of lumbar spine and femur and MRI of spine, femur, tibia and humerus bilaterally.

Results: Nine GD patients (six men and three women) were studied, with a mean age of 48 years (34–70), with an average time of evolution of the illness of 21 years (2–43). Currently, all patients receive ERT, with a mean duration of 10,5 years (1–16).

Most of them (n=6) started with bone symptoms such as pain and bone crisis. Before received ERT, patients developed the following bone abnormalities: bone infarctions in eight patients (89%), Erlenmeyer flask deformity in two patients, femur avascular necrosis in five patients, 80% of them required hip replacement (one of them bilaterally).

Also four patients had been splenectomized. The study with serial MRI demonstrated that once the ERT is initiated none of the bone manifestations (bone infarctions and avascular necrosis) progressed in any of the patients.

GD patients present mean values of 25OHD of 27.4±10.5 ng/ml. Insufficient vitamin D levels (25OHD < 30 ng/ml) were observed in most GD patients (87%), 14% showed deficient levels (25OHD <20 ng/ml). As for bone remodeling markers we found values of P1NP 60.75±34 ng/ml and βCTX 552±240 pg/ml. None of the patients received supplementation with calcium and vitamin D.

According to densitometry criteria 22% of the patients have osteoporosis and 22% are in the range of osteopenia. One pathological fracture was registered (vertebral).

Conclusions: ERT prevents progression of bone abnormalities in GD. Vitamin D insufficiency is frequent in GD and almost half of the patients have decreased bone mass.