Osteochondrodysplasias are a group of rare hereditary disorders of connective tissue, bone, or cartilage that cause the skeleton to develop abnormally.
In osteochondrodysplasias, the growth and development of bone, cartilage, and/or connective tissue is impaired usually because of 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 short stature (dwarfism). Dwarfism is defined as an adult height of 4 feet 10 inches (147 centimeters) or shorter 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 lethal form of short-limbed dwarfism called thanatophoric dysplasia that causes severe deformities of the chest and respiratory failure in newborns, which results in death.
Diagnosis of Osteochondrodysplasias
A doctor's evaluation
X-rays
Tests before birth
A doctor usually bases the diagnosis of osteochondrodysplasia on the symptoms, a physical examination, and x-rays of the bones.
Sometimes the abnormal genes responsible for osteochondrodysplasias can be detected, usually by a blood test. Analyzing the genes is most helpful for predicting the disorder 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 ultrasonography is done.
Treatment of Osteochondrodysplasias
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. However, vosoritide, a medication that may play a role in bone growth, is available as a possible treatment.
Because the basic genetic defects have been identified in most of the osteochondrodysplasias, genetic counseling can be effective.
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.
Little People of America: An organization providing community resources and medical support and information to people of short stature
