Osteochondrodysplasias are a group of rare hereditary disorders that cause the skeleton to develop abnormally and result in dwarfism or short stature.
In osteochondrodysplasias, the growth and development of bone, cartilage, or connective tissue is impaired. These disorders are caused by mutations in the genes that play an important role in the development of connective tissue. Connective tissue is the tough, often fibrous tissue that binds the body's structures together and provides support and elasticity.
Each type of osteochondrodysplasia causes different symptoms, but all osteochondrodysplasias cause dwarfism, which is markedly short stature. Dwarfism is defined as an adult height of less than 4 feet 10 inches (147 centimeters) in both men and women.
Some osteochondrodysplasias cause more shortening of the limbs than the trunk (short-limbed dwarfism), whereas others cause more shortening of the trunk than the limbs.
The most common and best-known type of short-limbed dwarfism is called achondroplasia. Children and adults with achondroplasia often have bowlegs, a bulky forehead, an unusually shaped nose ("saddle" nose), and an arched back. Sometimes joints do not develop their full range of motion.
There is a fatal form of short-limbed dwarfism called thanatophoric dysplasia that causes severe deformities of the chest and severe breathing difficulty in newborns.
Diagnosis of Osteochondrodysplasias
A doctor's evaluation
X-rays
Sometimes genetic testing
A doctor usually bases the diagnosis of osteochondrodysplasia on the symptoms, a physical examination, and x-rays of the bones.
Sometimes the abnormal genes that cause osteochondrodysplasias can be detected by genetic testing. Analyzing the genes can help doctors determine whether a baby has an osteochondrodysplasia before birth or can help doctors confirm a suspected osteochondrodysplasia after birth.
Some types of osteochondrodysplasia can also be diagnosed before birth during a prenatal ultrasound.
Treatment of Osteochondrodysplasias
Sometimes replacement of joints
Sometimes surgical lengthening of limbs and correction of bowlegs
If joint movement is severely restricted, surgery may be needed to replace joints such as the hip with artificial ones.
Doctors may be able to increase a person’s adult height by doing a surgical procedure to lengthen the limbs. A surgical procedure can also be done to correct bowlegs.
Although people with achondroplasia are short, treatment with growth hormones is generally not effective.
Vosoritide, a medication that may play a role in bone growth, is a possible treatment. However, whether this medication increases final adult height or what side effects it causes after long-term use are not known.Vosoritide, a medication that may play a role in bone growth, is a possible treatment. However, whether this medication increases final adult height or what side effects it causes after long-term use are not known.
Because the defective genes have been identified for many osteochondrodysplasias, genetic counseling can be helpful for people who have an osteochondrodysplasia and who want to have children.
Organizations such as Little People of America provide resources for affected people and act as advocates on their behalf. Similar societies are active in other countries.
More Information
The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.
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