Osteogenesis imperfecta (OI), also known as brittle-bone disease, is an 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, which can affect men and women of all races.
OI is believed to be due to a genetic defect that causes imperfectly formed or an inadequate amount of bone collagen, a protein found in the connective tissue.
Types of OI
There are four types of the disorder, with varying degrees of severity in the symptoms. Type I, mild cases, can usually be traced through the family.
Its symptoms can include:
- Bones prone to fracture, mostly before puberty, but sometimes in post-menopausal women
- Blue sclera, the normally white area of the eye ball
- Dental problems and brittle teeth
- Hearing loss beginning in the early 20s and 30s
- Near normal stature or slightly shorter
- Tendency toward spinal curvatures
- Triangular face
Type II is the most severe form and it affects newborns. It is sometimes fatal, although patients have lived to adulthood with it. Type II includes severe bone deformities with fractures and short stature.
Type III and Type IV have similar symptoms that are less severe than Type II.