Type I is the mildest and most common form of osteogenesis imperfecta. Type I OI can have the characteristics of an invisible disorder, meaning it is not apparent to a casual observer. Nearly all cases of OI, mild or severe, are caused by a dominant genetic mutation that affects the body’s production of type 1 collagen.
Symptoms
Osteogenesis imperfecta affects people in several ways and may vary from person to person. The most common signs and symptoms of Type I osteogenesis imperfecta are as follows.
- Bones are predisposed to fracture. Most fractures occur before puberty and again in later years.
- Joints are somewhat predisposed to other connective tissue injuries, such as dislocations.
- Skin may bruise easily.
- Height is variable and generally below average for age. Adult height may be similar or slightly shorter when compared with unaffected family members.
- Muscle weakness and lax ligaments.
- Spinal curvature (scoliosis) is frequently seen but tends to be mild.
- Scleras (whites of the eyes) usually have a distinctly blue or gray tint.
- Bone deformity is absent or minimal and occurs after fractures have occurred.
- Brittle teeth (dentinogenesis imperfecta) are possible.
- Hearing loss is possible, often beginning during teen or young adult life but perhaps starting sooner.
Some people with Type I OI are very mildly affected. They may have only a few fractures. They are of average or even above-average height; are able to walk and run; and have signs of OI that are barely noticeable, such as blue-tinted sclera or loose joints. Others may have more distinct symptoms. They may have several dozen or more fractures; sometimes use a wheelchair, walker, braces, or crutches for mobility; be somewhat smaller than the rest of their family; or require treatments such as rodding surgery.
Treatment
The treatment for children with Type I OI is fracture management, healthy diet, therapy to regain strength and mobility after fractures or surgery. Many orthopaedists prefer short-term casting for fractures, followed as soon as possible by a splint or brace that can be removed for appropriate exercise. Developing healthy lifestyle habits is an important part of managing OI.
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