Supplements in Rare Bone Diseases

Abstract Despite having different aetiologies, different rare bone diseases (RBDs) such as hypophosphatasia (HPP), autosomal dominant hypophosphatemic rickets (ADHR), X-linked hypophosphatemia (XLH) and osteogenesis imperfecta (OI) share common clinical features such as growth disturbances, pathological fractures, pseudo-fractures and chronic musculoskeletal pain. The role of micronutrients including minerals, trace elements and vitamin D in the physiological bone metabolism are well established. A significant share of RBD patients suffer from nutritional deficiencies due to the underlying disease or do not achieve the recommended daily intake (RDI) for micronutrients. The supplementation of micronutrients in RBDs should have the goal of achieving the RDI and promoting bone metabolism without increasing the burden of disease. Specific diets and an increased intake of specific micronutrients could potentially improve some of the disease symptoms, however special caution should be taken to avoid over-supplementation and to avoid adverse effects such as hypercalciuria, ectopic calcifications, GI-upset and nephrocalcinosis in case of calcium over-supplementation.