Brittle bone disease is more commonly known as osteogenesis imperfecta (OI). It is a rare, usually inherited disorder that causes bones to break easily due to the body’s low production of collagen. There are six different types of brittle bone disease. The last two types, Type V and Type VI have been recently identified, and many articles refer to only four different types. The type of brittle bone disease indicates the degree to which the condition may impact one’s life. While some people are severely affected by brittle bone disease, others are able to live a relatively normal life.

Low levels of collagen characterize Type I brittle bone disease. This type is the most frequently occurring and the least severe. Bones are likely to break easily before the onset of puberty. As well, those with Type I are prone to scoliosis, extreme curvature of the spine, and may need to wear a brace as teenagers to correct the curve.

Those with Type I brittle bone disease may also have poor muscle tone, be subject to early loss of hearing, and may show discoloration in the whites of their eyes. Joints may be loosened, causing some lack of coordination, resulting in easier breakage.

Type II brittle bone disease is extremely severe, with most affected children dying before age one. The bones are usually severely deformed and lung development is not normal. Respiratory infections are the primary cause of death in this type.

Type III, conversely, allows the body to produce enough collagen, but the collagen is of poorer quality. This type of brittle bone disease is progressive, with few symptoms shown in babies. As the child ages however, symptoms like those of Type I begin to emerge. Generally, severity increases with age creating significant deformity and disability. People with Type III may have a normal lifespan, but their life will be significantly impacted by progression of the disease.

Type IV brittle bone disease is also characterized by poor quality collagen but tends to be a milder form. Bone breakage is common before adolescence, like in Type I. In fact the disease follows an almost identical course to Type I. The differentiation is that Type I is caused by insufficient collagen, while Type IV is caused by sufficient collagen of poor quality.

Type V and Type VI are used to describe the way the bones develop, and are both basically subsets of Type IV. Type V brittle bone disease usually causes the bones to resemble meshing or webs. These imperfections result in easier breakage. In Type VI brittle bone disease, the bones appear to be scaled.

Brittle bone disease has no cure, so treatment aims toward reducing breakages and deformation. In Type I and Type IV, the bones appear to be more vulnerable to breakage during growth spurts, and breakages occur with even the simplest of injuries. Physical therapists work with children to help them build muscle tone to protect bones. Some patients undergo surgery to fuse the spine, which may help with posture and reduce curvature. However, bones are often so fragile that this surgery is quite risky.

Children with brittle bone disease often are afraid of trying new things because of the fear of painful breaks and injuries. Frequently, psychotherapy is used to address this fear. Physical therapists may also work with children to help them try out new positions in a safe environment. The condition can be difficult for all members of the family, and support groups can be of great help. There are OI Foundations in Europe, the US and Australia that can help guide families toward support and information regarding this challenging illness.