Osteogenesis imperfecta (O.I.) is called brittle bone disease because the bones of affected individuals break so easily “like glass.” Brittle bone disease is a rare hereditary disease that affects about 6,000 people in Germany. Osteogenesis imperfecta – meaning “incomplete bone formation” – has as its most striking feature an increased tendency to fracture bones. Affected children therefore sometimes suffer bone fractures even before birth.
Cause of bone fractures
The cause of this disease is a genetic defect in collagen metabolism. Collagen is the basic building block for all types of tissue – it provides support and stability for bones while keeping connective tissue elastic. Affected individuals do not produce enough collagen or only produce inferior collagen. Due to the lack of collagen, the bones have too little support. As a result, bones can become deformed and break at the slightest stress.
Disease progression of brittle bone disease.
Some people affected by brittle bone disease do not notice their disease until adulthood, while others suffer so many bone fractures in early childhood that they never learn to walk. Often, the bone fractures become fewer after puberty. During the healing of such fractures, an unusually large amount of bone material forms more quickly than average, which can lead to deformations at the fracture sites. These deformations can severely restrict the freedom of movement of O.I. patients. Experts distinguish between different degrees of severity:
- Type 1: Bones break very quickly but grow back together normally.
- Type 2: The first fractures happen already in the womb. The child rarely reaches the second year of life.
- Type 3: Severe spinal deformities lead to the patient often has to sit in a wheelchair.
Brittle bone disease: what are the symptoms?
The disease additionally affects all other tissues that contain connective tissue in their structure. Therefore, brittle bone disease can also extend to the skin, tendons, muscles, ligaments and other types of tissue – weak connective tissue occurs. Weakness of connective tissue can be recognized, for example, by stretch marks or spider veins. In addition to connective tissue weakness, other symptoms of brittle bone disease include:
- Lung and breathing problems
- “bruises” after a slight bump
- Deformation of limbs, chest and skull.
- Scoliosis (curvature of the spine).
- Conical curvature of the cornea
- Flaccidity of the muscles
- Hyperextensibility of the joints
- Short stature
- Hearing loss
Diagnosis of osteogenesis imperfecta
Diagnosis of brittle bone disease is usually made by collagen analysis of connective tissue. A specialist can also identify “brittle bones” on an x-ray by their almost translucent structure, which looks much whiter and denser in healthy people. Prenatal ultrasound can reveal deformed bones while the patient is still in the womb.
Various forms of therapy for brittle bone disease.
Because the symptoms of brittle bone disease vary widely, there is no generally accepted treatment recommendation. The hereditary disease persists throughout life and is not yet curable. There is no causally effective therapy yet. However, there are different therapeutic approaches that lead to an improvement of the life situation by stabilizing the disease state. These include – in addition to the prevention of new fractures – treatment with drugs that are otherwise used to combat osteoporosis. They are intended to increase bone density and thus prevent new injuries. Agents used as part of treatment for osteogenesis imperfecta include:
- Bisphosphonates
- Calcitonin
- Calciferols
- Fluoride
Nutrition as part of the treatment
A balanced diet can also support the therapy of brittle bone disease. Especially calcium and sufficient protein are essential for bone regeneration. Calcium, for example, is particularly found in kale, Emmental cheese, and Brazil nuts. Foods rich in protein include tuna and eggs. In addition, the sufficient intake of vitamin D is referred to, this is abundant in fish and mushrooms, for example.However, vitamin D3, which is important for bone formation, is only generated by sunlight on the skin.
Exercising the muscles as a complement to therapy.
Quite important in all therapeutic measures against brittle bone disease is – as far as possible – the training of the body to build up a supporting musculature. However, this should not risk further bone fractures. Well-suited movements are therefore swimming, aquaboxing, gymnastics and isometric exercises in which the muscles are alternately tensed and released. Unfamiliar movements should preferably be performed initially under the supervision of physical therapists or experienced trainers.
