Chondrodysplasias
The chondrodysplasias are a group of rare disorders of cartilage that cause the skeleton to develop abnormally.
In chondrodysplasias, the growth plate, which contains cartilage, does not make new bone cells. Thus, growth of bone is impaired.
Each type of chondrodysplasia produces different symptoms. Chondrodysplasias usually cause short stature (dwarfism). Some cause more shortening of the limbs than the trunk (short-limbed dwarfism); others cause more shortening of the trunk than the limbs. Some children and adults have short limbs, bowlegs, a bulky forehead, an unusually shaped nose (saddle nose), and an arched back. Sometimes, joints do not develop the capacities for their full range of motion.
A doctor usually makes the diagnosis based on the symptoms, physical examination, and x-rays of the bones. Sometimes the abnormal genes responsible for chondrodysplasias can be detected, usually by a blood test. Analyzing the genes is most helpful for predicting the disease before birth. Diagnosis of severe types before birth is also possible using other methods; in some cases, the fetus can be directly viewed with a flexible scope (fetoscopy), or an ultrasound is performed. Surgery may be needed to replace joints that have severely restricted movement with artificial ones.
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