Osteogenesis Imperfecta: What You Need to Know
Osteogenesis imperfecta is also known as brittle-bone disease.
It is a genetic (inherited) disorder characterized by bones that break easily without a specific cause.
An estimated 20,000 to 50,000 people in the United States have this disease.
Osteogenesis can affect males and females of all races.
Previously, there were considered to be four types of osteogenesis, but research has now shown that there are eight specific types of the disease.
There is no cure for the condition. Symptoms require life-long management.
What is osteogenesis imperfecta?
Osteogenesis Imperfecta (OI) is a condition characterized by frequent bone fractures from decreased bone density, which is caused by a defect in the gene responsible for making type 1 collagen. Type 1 collagen is the main component of bone matrix (the cellular structure from which bone develops) and ligaments. Deformity in the long bones of the legs and arms as well as in the spine is also common among individuals with OI. In the more severe forms of the condition, adult stature is small and a wheelchair is needed for mobility.
What causes osteogenesis imperfecta?
OI is a genetic condition that can be passed from parent to child, or an individual may be the first in their family to have it due to a spontaneous genetic mutation.
What are the types of osteogenesis imperfecta?
The four most common types of OI are 1, 2, 3 and 4:
OI type I: Mild form; patients have no bone deformities and a near normal adult height
OI type II: Extremely severe form with rare survival beyond birth
OI type III: Most severe form in children surviving the neonatal period (roughly the first four weeks after birth); severely deforming, extreme short stature
OI type IV: Intermediate form between type I and type III; mild to moderate bone deformities and variable short stature
There are four additional types of OI that are rarely seen and were discovered more recently. The severity and features of the condition vary according to the specific genetic defect. Generally, types 2, 3, 7 and 8 are the most severe types, type 1 is the mildest and types 4, 5 and 6 are moderate in severity.
What are the symptoms of osteogenesis imperfecta?
Symptoms of OI include:
Low bone density in early childhood
Bowing deformity of the long bones in the legs and arms
Spinal deformity such as scoliosis
Secondary symptoms of OI include:
The symptoms of OI may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.
How is osteogenesis imperfecta diagnosed?
Medical history, physical exam, radiographs and blood work for genetic testing are used to aid the clinician in reaching the diagnosis of OI.
Additional diagnostic tests may include:
X-ray: A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones and organs onto film
An examination of the ear, nose and throat (to detect hearing loss)
Treatment for Osteogenesis Imperfecta
To date, there is no known treatment, medicine or surgery that will cure OI. The goal of treatment is to prevent deformities and fractures and allow the child to function as independently as possible.
Young children with frequent long bone fractures and bowing deformity in their legs are offered surgical treatment with Fassier-Duval intramedullary rods. These rods are telescoping and will expand within the bone as the child grows. The rods offer a supportive structure, decreasing the frequency of fracture and increasing support while standing and doing light activities.
An endocrinologist is also an important member of the health care team. This specialist will determine if a medication should be used to decrease bone loss and therefore decrease the frequency of fractures in childhood.
Long-Term Outlook for an Individual with Osteogenesis Imperfecta
OI is a progressive condition that needs lifelong management to prevent deformity and complications. The interdisciplinary health care team helps the family to improve the functional outcomes and to provide support. The Osteogenesis Imperfecta Foundation can also be an important resource.