What is Osteogenesis Imperfecta?
Osteogenesis Imperfecta (OI), or brittle bone disease, is a condition where collagen, the protein that is responsible for bone structure, is low or of poor quality. The minerals in the bone are therefore not supported, making the bone weak and in turn making it fracture easily.
There are four main types of OI:
Type 1 is often mild and usually not diagnosed until later in childhood.
Type 2 is very severe and means that babies unfortunately do not survive. It is detectable in the womb on ultrasound.
Type 3 and the severe forms of Type 4 are possible to detect whilst the baby is in the womb, or shortly after birth. These types of OI result in numerous fractures, stunted growth and pain.
In order to know for certain that a person has OI, a DNA test must be performed. This can be carried out on a blood sample.
OI is a group of genetic disorders caused mainly by >1,350 different dominant and >150 recessive mutations. One child among 10-20,000 is born with OI and mutations in the collagen genes resulting in abnormal collagen microfibril assembly are most common.
The major clinical manifestations are atypical skeletal development, osteopenia (a medical condition in which the protein and mineral content of bone tissue is reduced), multiple painful fractures and short stature, but OI individuals also suffer from brittle teeth, hearing loss and hypermobile joints and have a higher risk of heart valve insufficiency, aneurysms and bleeding and coagulation deficiencies throughout their life time.
OI has a diversity of clinical presentation, ranging from the mild type 1 that only becomes evident in adulthood to the perinatally lethal type 2A/C. Type 3 OI is the most severe form that is compatible with survival into adulthood. Individuals affected by OI type 3 may experience hundreds of fractures in a lifetime. However, most commonly OI presents in childhood with multiple fractures after little or no trauma (type 1/4). Type 4 and 5 OI can be moderately severe, but are very variable. Life expectancy is not affected in milder OI types but may be shortened for those with more severe types.
Current treatments cover three main areas:
None of these treatments are curative and they do not address the underlying problem.