What is osteogenesis imperfecta ?
Osteogenesis imperfecta (also abbreviated as OI) or brittle bone disease is a rare, congenital and hereditary connective tissue disorder characterized notably by very brittle bones. By a gene mutation is the amount and / or the composition of the collagen type 1 (usually) different.
Osteogenesis imperfecta symptoms
OI is characterized by reduced bone strength. This allows broken bones (fractures) and adhesions (deformations) of the arms, legs, spine, chest and / or skull easily occur. Also, the joints can about mobile (hyperlaxity) are. In some cases, the bite is also affected, in which one speak of dentinogenesis imperfecta. In addition come several ancillary phenomena as blue sclera (white of the eye), bulging eyes (protrusion) and deafness. Other symptoms may include fatigue, pain and / or excessive perspiration. Bruising and nosebleeds also easily occurs. The symptoms can be very different between patients in type and severity.
Osteogenesis imperfecta diagnosis
The diagnosis is made on the basis of the above-mentioned symptoms. It is remarkable that babies with more severe types of OI often are born with broken bones. Also, patients often at a young age suffered multiple fractures. Radiological examination can confirm the diagnosis. In addition there is genetic testing possible to determine with certainty the diagnosis and to identify the exact mutation.
OI / Osteogenesis imperfecta types
There are six different types of osteogenesis imperfecta.
- Type I is the most common and is the mildest form. The (normal) collagen is present is reduced. There are also in this type of indication that there is an increased risk of osteoporosis, around young adulthood. However, this has not been proven to date!
- Type II: Seriously. The quality or the quantity of the collagen is insufficient. They often die in the first year because of respiratory problems and brain haemorrhages.
- Type III: Seriously, can give before birth fractures. Often have a normal life, but with slowly progressive symptoms and deformities.
- Type IV: There is sufficient collagen, but of poor quality. Bone deformities especially from puberty.
- Type V and VI: Similar symptoms 4 and discovered only recently. Distinguished by a different histology.
Osteogenesis imperfecta treatment
There is no treatment of the cause of the disease. However, the possible symptoms and effects can be controlled. This requires a multidisciplinary approach. Symptomatic therapy consists of treatment of fractures, surgical correction of deformities and adequate pain relief, even in young children. Usually, the following is a shortest possible period of immobilization (eg tape, splint or plaster). Often treatment with bisphosphonates may improve bone density.
Heredity
Osteogenesis imperfecta is a congenital condition. Inheritance is usually autosomal dominant and autosomal recessive times. In most cases, a person OI by inheritance by an affected parent or by parents who are carriers of the abnormal gene. However, spontaneous mutations occur. In approximately 25-30% of the patients both parents are healthy.
Prevalence
The worldwide prevalence is estimated to at least 1 / 15,000 inhabitants. In the Netherlands, there are more than 1,000 people with OI. The exact prevalence and incidence figures are unknown because patients with no obvious symptoms are not always diagnosed. Annually are born in our country 10-15 OI children (in 200,000 births). The GP with a standard practice of 2,500 patients who operates thirty years, based on these figures exceeding one patient with OI in his practice. Because of the hereditary aspect will, however, a practice sometimes several patients from one family.
Osteogenesis imperfecta and anesthesia
Because of the frequent breaking bones is often require surgery. Additional measures are necessary to protect the patient. The blood pressure cuff should not be inflated too long and do not measure too often. The position of the patient during an operation is extremely important. Manipulations with the neck or other body parts must take place carefully. Damage to the teeth can easily occur.