Osteogenesis Imperfecta: update on presentation and management.

Osteogenesis Imperfecta (OI) is a rare heritable condition characterized by bone fragility and reduced bone mass. Traditionally OI was classified into OI types I to IV and thought to be only due to a defect in the collagen gene, however through the discovery of the new types of OI-V to VII, breakthroughs have been made in understanding the pathophysiology of autosomal recessive OI and new genetic mutations, such as in CRTAP and P3H1 genes. OI can present at any age and be difficult to diagnose because of the wide phenotypic variation. Awareness of the new forms of OI, the differential diagnosis and the limitations of diagnostic tools, all help to correctly diagnose and manage a patient with OI. Cyclical intravenous pamidronate is now the standard of care for moderately to severely affected children with OI, given in combination with good orthopedic, physiotherapy and rehabilitation programs. The benefits and short term safety of cyclic bisphosphonates have been amply reported in the literature; however their long term effects are still under investigation. Newer more potent forms of bisphosphonates such as zoledronic acid have undergone and are still being subject to international multicentric drug trials and are beginning to replace pamidronate in some centers.