Acrodysostosis

Genetic changes that occur while the fetus is growing can cause disorders that are present at birth. These are sometimes referred to as "congenital disorders." Acrodysostosis is one such condition, albeit a rare one.

Acrodysostosis is a skeletal disorder. It causes problems with bone formation and growth. The disorder is also associated with mental retardation and learning problems. Only 40 to 50 cases of this disorder have ever been diagnosed (National Organization for Rare Disorders, 2008).

Acrodysostosis is also known as:

• Arkless-Graham
• acrodysplasia
• Maroteaux-Malamut

Doctors do not know the exact cause of acrodysostosis. Research into the disorder has shown that there may be a genetic link. This means that if a parent has the disease, he or she has a higher chance of having a child with the condition. Many cases of acrodysostosis develop sporadically with no apparent cause. Older age of the father has also been noted to be a potential cause for the disorder.

The symptoms of acrodysostosis are different for each person. They also will vary depending on the extent to which an individual’s bones are malformed. The degree of mental retardation may also vary between individuals.

Children with acrodysostosis typically have unique physical features. These include:

• short and malformed bones in the hands and feet (peripheral dysostosis)
• underdeveloped short flat nose (nasal hypoplasia), also known as a "pug" nose
• premature growth of bones, especially in the arms and wrists
• underdeveloped jaw bone (maxillary hypoplasia)
• eyes that are spaced far apart (ocular hypertelorism)
• extra folds of skin on the nose (epicanthal folds)

Physical features of the disorder often develop over time. Infants with acrodysostosis are often smaller than average when they are born.

In addition to these physical features, there are other symptoms that can occur:

• mental retardation
• learning disabilities
• middle ear infections
• swelling and pain in the joints (arthritis)

Approximately 80 percent of children with acrodysostosis have some type of learning disability (National Organization for Rare Disorders, 2008). Symptoms may not be detected until early childhood.

If you notice any of these symptoms, you should contact your doctor. Acrodysostosis is not life threatening, but early diagnosis will ensure early treatment. The outlook is better when treatment is provided earlier.

Diagnosis of acrodysostosis can be made by a doctor. The doctor will perform a physical exam if your child has symptoms of this disorder. During the exam, the doctor will look for:

• deformities in the bones of the hands and feet
• delays in growth
• problems with the skin, genitals, and teeth
• short head size
• short arms and legs
• small nose that is upturned
• unusual facial features, including a jaw that sticks out
• eyes that are spaced far apart

The doctor will also ask you about family history of the disease. He or she may also order an X-ray. An X-ray can show calcium deposits on the bones (stippling). An X-ray will also show if the bones are normal length.

There is no cure for acrodysostosis. Treatment of the condition will be based on the symptoms that are present. Physical therapy may be helpful to treat mobility or movement problems. Jaw problems or disorders may be treated with orthodontic supports. Braces can be used to correct misaligned teeth. Surgery may be recommended in some cases for correcting bone or jaw problems.

Children with mental retardation or learning disabilities may benefit from services that help them to reach their full potential. Services can include:

• special education
• social support
• vocational services

If you have a child with acrodysostosis, you may want to consider participating in a clinical trial. Clinical trials are used to see if new medications or therapies are effective for treating a particular disorder. You can ask your doctor about clinical trials. You can also get information from the Internet. The website www.clinicaltrials.gov lists all current clinical trials that are being sponsored by the U.S. government.

Outcomes for a child with acrodysostosis vary depending on the severity of his or her symptoms. Generally, individuals with this condition do well.

Children with severe skeletal problems may have additional health complications as they grow older. These include:

• arthritis
• carpal tunnel syndrome
• limited range of motion in the joints, especially the spine, hands, and elbows

Early intervention to treat these conditions can improve an individual’s outlook.

It may not be possible to prevent acrodysostosis. You may want to seek genetic counseling if you have a family history of this disorder. Genetic counseling can help you assess your risk of having a child with acrodysostosis.