Brittle bone disease is a rare genetic disorder that causes bones to break easily because of problems with collagen production and quality in the body. Also known as Osteogenesis Imperfecta (OI) or Lobstein syndrome, there are eight different types of this condition, which vary in severity. Though there is no cure for brittle bone disease, the symptoms are often manageable. Besides the effect it has on the body, OI also often has psychological and social effects, and may be mistaken for child abuse in some situations.
Types of OI
There are eight different types of brittle bone disease, which differ in terms of the specific genetic variation that causes them, how the collagen is affected, and what other symptoms occur along with the bone brittleness. Type I is the mildest, while Types II and VIII are considered the most severe. Types III through VII are all considered deforming, but the collagen of those with Types V and VI looks different from that of those with other types.
Of the eight types, types I through V are caused by autosomal dominant genes, meaning that a person would only need to get the abnormal gene causing the disease from one parent. Types VII and VIII are autosomal recessive, meaning that both parents have to pass on the abnormal gene for the child to develop the condition. It's not clear whether Type VI is dominant or recessive.
The symptoms of OI vary depending on what type it is, but generally speaking, people with this condition are short, tend to have a lot of fractures and bruises, a higher than average voice, and brittle teeth. About half of people with OI are hearing impaired, because the bones that transmit sound in their inner ears break easily or are deformed. Additionally, they tend to get overheated easily, and may sweat a lot. Many also have blue tinges in the whites of their eyes, though people with Type IV don't. Those with Type V usually have collagen cells that look like mesh, while those with Type VI have collagen that has a fish scale look.
Making a diagnosis of brittle bone disease can be difficult, since not all people have immediately visible symptoms. Also, bone density tests and X-rays aren't reliable, since the bones of those with OI tend to show up as normal, unless they've been broken many times. A diagnosis can be made by observing the type of collagen a person's cells produce or by looking at their genes for the types of mutations that cause collagen abnormalities, but neither is a foolproof method.
Brittle bone disease has no cure, so treatment is focused on 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 can 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, but the bones are often so fragile that this surgery is quite risky. There's no specific medications that are generally used to treat this condition, but some people respond well to osteoporosis drugs.
Social and Psychological Effects
Although the condition is most often inherited, a genetic mutation can occur in about 25% of cases that does not come from a parent. If a child with undiagnosed OI has a lot of unexplained broken bones, health authorities may suspect the parents of abuse. A DNA or collagen test can usually clear up confusion, and those kids with OI who can't be identified through genetic testing may be diagnosed accurately by a trained expert in the field through distinctive physical features.
Children with brittle bone disease are often afraid of trying new things because of the fear of painful breaks and injuries. Frequently, psychotherapy is used to address this fear, and physical therapists can help kids figure out the safe limits of the body. Many also develop body image concerns as teenagers, which psychotherapy and support groups can also help with.