Bone density changes with enzyme therapy for Gaucher disease

Gaucher disease is the most common lysosomal storage disease. Enzyme replacement therapy engenders improvement in hematological and visceral parameters; however, improvement in bone density (BMD) with treatment has not been confirmed. This study presents follow-up of BMD in the first ten patients in Israel treated with low-dose recombinant enzyme for up to 108 months. BMD at femoral neck and lumbar spine was determined by dual-energy X-ray absorptiometry (DEXA) at the start of the trial, after 3-6 months, after 18-24 months, and at the most recent follow-up. BMD in all patients was very low at onset and never normalized. There was a decrease in BMD in all patients at 3-6 months. Older patients (four women, two men; >30 years of age) showed some improvement in BMD during treatment. Younger patients (four females; 18-23 years of age) did not show a statistically significant improvement. These findings might reflect the failure of patients with Gaucher disease to achieve expected peak bone density at appropriate chronological milestones despite treatment. Nonetheless, the z-scores of the older patients were better than those of the younger patients, implying some catch-up period. Yet, some patients with Gaucher disease evince rapid onset of osteoporosis in early adulthood. Enzyme treatment per se, as well as attendant improved well-being and increased physical activity, may induce amelioration in BMD at this later stage. One may consider adding anti-osteoporosis therapy in young adults to induce earlier "catch up" to peak bone mass, and then enzyme replacement in later adulthood to prevent decrements in bone mass related to Gaucher cell infiltration.