Orthopedic aspects of skeletal dysplasia in children.

Significant advances in the management of skeletal dysplasia have occurred during the past year. A revision of the Paris classification of constitutional disorders of bone has been proposed. New mutations have been identified in several disorders that confirm genetic heterogeneity within similar phenotypes. New clinical data of growth, fracture rates, and incidence of major skeletal and extraskeletal changes as well as the natural history and treatment of spinal deformities in osteogenesis imperfecta have been reported. Pilot studies of short-term growth hormone therapy in patients with achondroplasia and hypochondroplasia and nasal-osteocalcin therapy in osteogenesis imperfecta patients has been described, but the long-term effectiveness of these treatments remains to be determined. Extensive limb lengthening continues to be an important part of the treatment of patients of short stature in Europe, but complication rates continue to be very high. Both the current and future roles for this type of therapy are highly controversial. The potential for enzyme replacement therapy and retrovirus-mediated gene transfer in a variety of mucopolysaccharidosis disorders has been given new meaning by studies with cultured fibroblasts, which suggest that active enzymes can enter into and be synthesized in abnormal cells resulting in normalization of substrate turnover.