Compare and contrast endochondral and intramembranous ossification. Describe the main steps in the development of a long bone. Describe the main events in the development of the limbs. Increased limb growth is produced by some nerve malformations and by increased blood supply to the growth plate. A seemingly normal infant, in a matter of a few years, may be transformed into a mentally retarded, physically deformed, severely handicapped individual.
Death occurs in childhood or early adult life.
The main histological features are the presence of inclusion bodies composed of mucopolysaccharides within cells of the growth plate, the C.N.S. and parenchymal and connective tissue cells. In this disease keratosulphate accumulates in cartilage and cornea. Severe stunting becomes apparent in the second and third year of life. The joints then become involved and osteoporosis becomes prominent. The cartilage has abnormal chemistry, and the problem is a systemic metabolic disorder.