What Is Osteogenesis Imperfecta?
Osteogenesis imperfecta (OI) is sometimes called brittle bone disease. It is a genetic disorder that affects the quality (and sometimes the quantity) of the bone. This can cause bones to break much easier than in a person without OI.
There are many different types of OI. Some can be very mild where the diagnosis may not be obvious, and some can be very severe leading to early death. In most cases of OI, the largest number of fractures happen during childhood and then decrease once children are done growing. Sometimes fractures can increase again later in life.
What Causes Osteogenesis Imperfecta?
OI is caused by a mutation in a gene. Over 90 percent of cases are caused by a mutation in one of two particular collagen genes (COL1A1 or COL1A2). Collagen is what helps form the structure of the inside of the bone. In these cases, there is usually a family history of OI unless it is a new mutation in the child. There have been a number of other genes identified that cause OI as well, and there are currently 15 unique types of OI that are reported.
What Are Signs & Symptoms of Osteogenesis Imperfecta?
- Multiple fractures, especially from low or no trauma
- Deformed bones (including in ribs/chest wall)
- Bone pain
- Low bone density and/or osteoporosis
- Small size of short stature
- Easy bruising
- Loose joints (joint hypermobility)
- Low muscle tone or muscle weakness
- Blue or gray sclera (white part of the eyes)
- Discolored brittle teeth (dentinogenesis imperfecta)
- Triangular face shape
- Spine curve (scoliosis)
- Compression of the spine
- Breathing problems (usually if rib deformities)
- Fragile skin and blood vessels
- Hearing loss (especially near 20 or 30 years old)
- Hip problems where hip is angled different (coxa vara)
How Is Osteogenesis Imperfecta Diagnosed?
Osteogenesis imperfecta can be diagnosed by clinical exam. This is more likely if there are obvious clues on the examination like bone deformities, blue or gray sclera and dentinogenesis imperfecta (DI). DI is when teeth can appear yellowish or translucent and may chip or crack easily. Otherwise, a genetic test can be sent which can help decide or confirm what type of OI a child might have. This is a blood test and should be ordered by a geneticist or a person who diagnoses and treats patients with OI regularly.
OI can also be suspected and diagnosed prenatally. Chorionic villus sampling (CVS) can detect the genetic defects and it is possible that if there are more obvious bone deformities, it can also be noted on a prenatal ultrasound.
How is Osteogenesis Imperfecta Treated?
There is not a treatment yet that will fix or cure OI, but there are many interventions that can help improve the quality of life of someone with OI. This can include nutrition, therapies, fracture care, medications and possibly surgeries.
While the nutrition of all children should focus on getting a well-balanced diet, including calcium and vitamin D rich foods, it is especially important in children with OI. It is important though to get the right amounts of calcium and vitamin D, so taking large amounts of supplements may not be the answer. It is important to work with your child’s health care team to get help with this.
Occupational and physical therapy can be helpful to children with osteogenesis imperfecta. Physical therapy can assist with improving muscle strength and movement and occupational therapy can assist with improving fine motor skills. Both can help not only with improving strength and ability, but also helping children to not lose milestones related to their muscle and bone weakness and injuries. Some adaptive devices might also be identified and used to help children move through their regular daily activities more successfully.
Fracture management is an important part of caring for a child with OI. Children with OI need immobilization of the broken bone to allow for healing and protect them from further damage, but the time spent in a cast can sometimes weaken the bones and muscles even more. Because of this, children with OI are given casts or splints for the shortest amount of time needed to allow for healing without losing other strength or functioning.
Sometimes if a child with OI is fracturing bones too much, additional medications are given to improve the density (strength) of the bones and hopefully decrease the amount of fractures. These medications are called bisphosphonates and are a type of osteoporosis medication that is used to treat osteoporosis in adults. These are most commonly given as infusions through an IV.
Surgery may be used to support the spine or to support the long bones in the legs. It may also be needed to correct a deformed bone or a fractured bone.
What Are the Long-Term Effects of Osteogenesis Imperfecta?
- Because of the risk of fracture and bone deformity, mobility and the need for any additional devices or support for moving around safely is very important long term.
- Additionally, since hearing loss can develop in early adulthood, ongoing evaluation of a person’s hearing should be performed.
- Person’s with OI need to have their breathing status evaluated regularly because they can be at higher risk for asthma and pneumonia and breathing problems into adulthood.
- Oral care is very important throughout life with OI, especially if that person has dentinogenesis imperfecta where their teeth can be quite brittle.
- Heart valve problems can be an issue in adults with OI so they should have cardiac monitoring for this.
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