Osteochondrodysplasia

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at September 5, 2016
StartDiseasesOsteochondrodysplasia

Osteochondrodyplasia, also known as skeletal dysplasia and a type of dwarfism, is a group of developmental disorders that affect a person’s bones and connective tissues.

Contents

Definition & Facts

There are over 350 known conditions that fit into this category of disorders, and they range from the fatal types (thanatophoric dysplasia) to the rarely fatal types (metatropic dwarfism). Each individual disorder in the osteochondrodysplasia family is a rare disorder; however, when all of the disorders associated with skeletal dysplasia are combined, osteochondrodysplasia occurs in 1 out of every 5,000 births.

Osteochondrodyplasia is defined as a group of dissimilar disorders (a heterogeneous group) that are usually associated with complications of skeletal development and differing degrees of dwarfism. Skeletal dysplasia is a rare disorder, meaning it only affects a small percentage of the population.

It is a genetic disorder that arises from genetic mutations in numerous families of genes, which tend to encode various types of proteins, such as tumor suppressors and chaperones (protein). These genetic mutations cause abnormalities in how the bones and connective tissue develop, which result in a wide variety of complications. These complications can ultimately lead to death.

Symptoms & Complaints

One of the main signs of osteochondrodysplasia is a disproportionately short stature. This means that the bones and connective tissue grow abnormally with respect to the rest of the body. The result is a person of relatively short stature when compared with an average person.

In addition, someone with skeletal dysplasia will have abnormally sized and/or shaped skulls, trunks, and limbs. Aside from these common symptoms, the signs of skeletal dysplasia vary quite a bit because skeletal dysplasia encompasses such a wide range of disorders.

Different disorders that fall under the umbrella term of osteochondrodysplasia can differ in what part of the skeleton is affected and the severity of the developmental issues. Some of these disorders are associated with vision problems and hearing problems, such as glaucoma and hearing loss.

Others may cause minor deformities like stubby fingers and the duplication of fingers and toes. Some patients may have missing bones, fractured bones, joint pain, or scoliosis. However, others can have even more severe impairments that result in developmental delays and impaired cognition. Some of the complications that arise from this group of disorders can even be fatal.

Causes

There are a number of causes of skeletal dysplasia, but almost all of them are the result of a genetic defect. They result from mutations in various families of genes. These genes tend to encode specific proteins associated with skeletal development. They include genes that code for enzymes, cellular transport proteins, and transcription factors, along with numerous other proteins.

Diagnosis & Tests

The first step to diagnosing a patient with osteochondrodysplasia is through physical examination. Warning signs can present themselves as early as birth, for instance, if the child is born with a short stature. However, in other cases, the child might be born with normal stature, but later down the road, they start to have developmental issues. They may fail to grow as much as expected. Other times, it might be noted that part of the body, such as the skull, is not growing in proportion with the rest of the body.

Once these symptoms have been noted, a doctor is likely to perform a more thorough exam. This will include getting a complete family history for the patient and, most likely, performing routine measurements of the patient, such as height, weight, head circumference, and measurements of the upper and lower half of the body.

To further assess the type of skeletal dysplasia present, a doctor is likely to order X-rays, magnetic resonance imaging (MRI) scans, and computed tomography (CT) scans. This will give the doctor a more detailed picture of what is possibly going wrong. Finally, genetic and molecular analysis can be used to determine the exact type of skeletal dysplasia by identifying the exact genetic mutation present.

Treatment & Therapy

Treatment for osteochondrodysplasia is dependent on the type of disorder that a patient is suffering from. In addition, it is necessary to take a multidisciplinary approach to treat the various symptoms exhibited by patients with these disorders. In some instances, patients will be prescribed growth hormones to assist with growth, but most will still end up being shorter than average.

Because joint pain is a common issue in those with skeletal dysplasia, collagen injections to help with cartilage buildup in joints is common. In addition, joint replacements are routinely performed on people suffering from osteochondrodysplasia.

In other instances of those with skeletal dysplasia, surgery is necessary. In many instances, it becomes necessary to remove sections of bones that are causing complications. One instance of this is seen in achondroplasia. Achondroplasia causes the base of the skull to shorten, which causes the foramen magnum, a hole at the bottom of the skull, to be smaller than normal. This leads to the compression of the spinal cord, which can ultimately lead to death. In order to treat it, doctors must perform surgery to remove the portion of the bone that is compressing the spinal cord.

Surgery may also be used to lengthen a patient’s bones; however, this surgery has many likely complications attached to it, and its use is somewhat controversial at this time. Aside from surgery, people with skeletal dysplasias are recommended to have eye examinations and hearing examinations on a regular basis to better assess and treat potential hearing and sight issues that arise from certain disorders in this spectrum. There are numerous other treatments associated with osteochondrodysplasia, depending on the exact disorder the patient is suffering from.

Prevention & Prophylaxis

Osteochondrodysplasia is a group of genetically inherited disorders. As of right now, there are no known ways to prevent the disorders from arising. However, genetic testing can assess the likelihood, if any, of passing on these genetic mutations to one’s offspring.

By looking at the genetic makeup of two prospective parents, a doctor can inform patients if there is a significant risk to their children of developing skeletal dysplasia. This can prevent possible issues arising in the future, but it is not an exact or certain method of prediction or prevention.