What is diastrophic dysplasia?

The word “diastrophic” comes from a Greek word meaning distorted. Diastrophic dysplasia is a condition with many severe skeletal abnormalities because there is involvement with ears, the spine, long bones and feet.

Diastrophic dysplasia is a rare genetic disorder that is autosomal recessive, meaning an abnormal gene is received from each parent. The condition causes decreased sulfate content in the body, which affects cartilage. This, in turn, affects bone growth and height. The average height of people with diastrophic dysplasia is 50 to 53 inches. The taller the patient, the less severely he or she is affected.

What are the characteristics of diastrophic dysplasia?

Patients with diastrophic dysplasia may have some or all of the following:

• Hitchhiker thumbs — thumbs that bend backward when extended
• Prominent cheeks
• Flat nasal bridge
• Cleft palate
• Ear deformities
• Abnormal cartilage in the trachea

Skeletal abnormalities may also occur from the cervical spine (neck) down to the feet. This can cause additional symptoms, including:

• Cervical instability
• Cervical kyphosis, meaning the neck has an abnormal curve
• Scoliosis, or a sideways curvature of the spine, but many do not exceed 50 degrees
• Hip and knee flexion contractures, meaning the hips and knees cannot fully straighten
• Hip and knee degenerative changes, meaning the cartilage deteriorates, leading to painful arthritic changes
• Subluxations (partial dislocations) of the shoulders and radial head (the end of the radius bone at the elbow)
• Clubfeet, meaning the feet are stuck in a “turned in” position

Diastrophic Dysplasia Diagnosis

The doctor makes the diagnosis of diastrophic dysplasia with a complete medical history, physical examination and diagnostic tests.

Diagnostic procedures may include:

• X-rays of the spine and lower extremities
• MRI scans of the cervical spine if cervical kyphosis is present with neurological symptoms, such as weakness and increased reflexes
• Arthrograms, or injection of dye in the hips, knees and/or ankle to assess cartilage in the joints

Diastrophic Dysplasia Treatment

Treatment for diastrophic dysplasia varies depending on the associated orthopaedic conditions:

• Clubfeet — they can be corrected with casting and surgery to get the foot into a more normal position.
• Scoliosis — bracing can be used for mild curves and in very young children, but if there is a large curve (greater than 50 degrees), a spinal fusion is generally recommended.
• Cervical kyphosis — if progressive with neurological changes, treatment may include a posterior cervical fusion with possible placement of a halo.
• Hip and knee flexion contracture — this may need to be straightened with casting and surgery to improve walking ability.
• Hip and knee arthritis — total joint replacements may be required if the pain becomes severe.