Brittle Bone Disease: Severity, Treatments, and Causes

Osteogenesis imperfecta (OI), commonly called brittle bone disease, is a lifelong, genetic disease that causes a defect in the production of collagen protein. Collagen is an important protein that helps to support the body; think of it as the scaffold upon which the body is built.

People with osteogenesis imperfecta have soft bones that break (fracture) easily. They may also have bone deformities, such as bow legs, a curved spine, or a barrel-shaped chest. The goal of treatment is to prevent deformities and fractures and help the affected person function as independently as possible.

This article explains the causes and symptoms of brittle bone disease. It also covers how OI affects daily life, and how it is treated.

Brittle Bone Disease Symptoms

 Typical problems seen in people with osteogenesis imperfecta include:

• Bone fragility
• Bone deformities
• Barrel-shaped chest
• Curved spine (scoliosis)
• Short stature
• Triangle-shaped face
• Muscle weakness
• Easily bruised skin
• Soft, discolored teeth
• Hearing loss in early adulthood
• Bluish or greyish sclera (whites of the eyes)
• Loose ligaments

Osteogenesis imperfecta gets its more common name, brittle bone disease because children with the condition are often diagnosed after sustaining multiple broken bones.

The symptoms of osteogenesis imperfecta vary greatly between individuals. Some children are diagnosed very early in life, while in others it can be more challenging to detect the condition. Multiple fractures due to low-energy injuries should raise suspicion of an underlying condition such as OI.

Brittle Bone Disease Severity

Osteogenesis imperfecta is classified into eight types:

• Type I: The mildest and most common form, involving few fractures and deformities
• Type II: The most severe type, characterized by fractured bones at birth and underdeveloped lungs; Babies born with this type usually die within a week of birth
• Type III: The most severe type of OI seen in babies who do not die at birth, characterized by breathing and swallowing difficulties and deformities of the head and face
• Type IV: Fractures typically begin around when a baby starts crawling or walking; The child may develop deformed arms and legs
• Type V: Similar to type IV, but with thickened skin areas, called hypertrophic calluses, in areas where bones are fractured
• Type VI: A very rare form that is similar to type IV but with more severe symptoms
• Type VII: May be like types II or IV, characterized by a shorter stature and shorter limbs
• Type VIII: Similar to types II and III with very soft bones and growth problems

What Causes Osteogenesis Imperfecta?

Osteogenesis imperfecta is due to a genetic mutation in the gene that directs the body to produce collagen. Osteogenesis imperfecta can either be passed on from a parent who has the disease, or it can occur as a spontaneous mutation in a child.

Most cases of osteogenesis imperfecta that are passed from parents are due to a dominant mutation, which comes from one parent who has osteogenesis imperfecta. A small number of cases are due to recessive mutations and come from a gene from both parents, neither having the disease.

Osteogenesis Imperfecta Treatment

Currently, there is no known cure for osteogenesis imperfecta. The primary focus of treatment is on preventing injuries and maintaining healthy bones.

Lifestyle Changes

Ensuring that children with osteogenesis imperfecta eat a nutritious diet, get regular exercise, and maintain a healthy weight is fundamentally important. Often children with osteogenesis imperfecta will require ambulatory aids, braces, or wheelchairs.

Surgery

Surgical treatment of osteogenesis imperfecta depends on the severity of the condition and the age of the affected person. In very young children, many fractures are treated the same, as if the child had no underlying condition. However, surgical stabilization of fractures becomes more common, even at a young age.

Broken bones in children with osteogenesis imperfecta are often treated with surgery in order to stabilize the bones and prevent deformities. Intramedullary rodding, where a metal rod is placed down the hollow center of the bone, is often used to help support the fragile bone and prevent deformity of the bone.

Scoliosis is usually treated aggressively as the problem tends to progress in children with osteogenesis imperfecta.

Medications

The role of medications in the treatment of osteogenesis imperfecta is evolving, but recent studies show a benefit of treatment with bisphosphonates and calcium supplements. The rationale is that these treatments will strengthen the bone and decrease the frequency of fractures. Research is also being conducted in the use of growth hormones and genetic therapies.

Living with Osteogenesis Imperfecta

Osteogenesis imperfecta is not just a physical condition. The effects of osteogenesis imperfecta extend into every area of life, and can take a toll on one's emotional well-being and self-esteem.

People with osteogenesis imperfecta live with chronic pain, tiredness, bone deformity, and fractures that restrict their mobility and day-to-day life, making it difficult to parent, maintain relationships, hold down jobs, and participate in physical activities.

Furthermore, the stress of wondering when the next fracture will occur or how long one can expect to live can lead to immense stress and emotional exhaustion. For this reason, many people with brittle bone disease benefit from emotional support in the form of support groups or counseling.

Osteogenesis imperfecta often poses a financial burden, too. According to one study, the cost of caring for a child with osteogenesis imperfecta can range from $1,000 to $20,000 or more per year. The amount can vary, but may include the cost of treatments, mobility aids (i.e., home stairlifts and wheelchair ramps), travel costs to see specialists, and missed work.

For all people living with osteogenesis imperfecta, as well as their families, learning to cope with the disease is important for maintaining and improving quality of life. This can take many forms, but may include focusing on social or academic activities rather than physical activities, and connecting with others who have OI in the form of support groups.

Summary

Osteogenesis imperfecta, also called brittle bone disease, is a lifelong genetic disease marked by soft, fragile bones, bone deformities, short stature, and other features like muscle weakness and hearing loss. There are eight different types of osteogenesis imperfecta, ranging from type I, which causes only mild fractures and deformities, to type II, which is usually fatal within one week of birth. Treatment may involve a combination of lifestyle changes, medications, and surgery, with the goal of helping the affected person function as independently as possible.