Osteogenesis Imperfecta

Connective Tissue Disorder

Osteogenesis imperfecta (OI) is a genetic disorder which leads to bones that break easily, usually from little or no visible cause.

Symptoms

OI may manifest itself if 1 or more of the following symptoms is present:


  • Blue sclerae

  • Triangular facies

  • Macrocephaly

  • Hearing loss

  • Defective dentition

  • Barrel chest

  • Scoliosis

  • Limb deformities

  • Fractures

  • Joint laxity

  • Growth retardation

Pathogenesis

OI is caused by genetic defects that affect the body’s ability to make strong bones. In some cases of OI, a person either has too little or a poor quality of type I collagen due to a mutation in one of the type I collagen genes.

Diagnosis

Sometimes it is possible to diagnose OI based on clinical features. However, biochemical (collagen) or molecular (DNA) tests can be performed to diagnose OI in some situations. Both the collagen biopsy test and DNA test can detect almost 90% of all type I collagen mutations.

Treatment

There is no cure for OI. There is treatment available for preventing or controlling the symptoms, maximizing independent mobility, and maintaining optimal bone mass and muscle strength. Care of fractures, surgical and dental procedures, and physical therapy are often treatments used for people with OI. Use of wheelchairs, braces, and other mobility aids are also common. Exercise helps promote muscle and bone strength, which can also help prevent fractures. Swimming and water therapy are common exercise choices for people with OI, because water allows independent movement with little risk of fracture. Walking is also a common exercise for patients with OI.

Prognosis

The prognosis for a person with OI depends on the number and severity of symptoms. Respiratory failure is the most common cause of death for people with OI, followed by accidental trauma. Despite the severity of the disease, most people with this disorder can live successful lives.

Epidemiology

It is unknown how many cases there are exactly in the United States but it is estimated to be in the range of 20,000 to 50,000. The disease can present itself at any age, but it occurs in about 1 out of every 20,000 births.