Brittle bone disease

Bone consists of solid connective tissue (collagen), which is fibrously entangled. Limestone salts are ultimately deposited in this structure, which give the bone its final strength and mineralize it. In vitreous bone disease there is a gene mutation on chromosomes 7 and 17, which contain the information for the formation of the most important collagen for bone, collagen type 1. This mutation causes collagen type 1 to be produced incorrectly. In addition, the twisting of the individual collagen fibers is disturbed, resulting in reduced strength and stability of the bone.

General information

Brittle bone disease (lat. : Osteogenesis imperfecta) is a disease characterized by increased bone fragility. Figuratively speaking, bones break as easily as glass, which gives the disease its colloquial name.

In Germany about 2. 500-4. 500 people are affected by the glass bone disease. This corresponds to about four to seven cases per 100,000 inhabitants.

Inheritance

The brittle bone disease can be hereditary. If it has already appeared in a family, it is inherited autosomal-dominantly, i.e. children of ill parents also develop this disease, in so far as they receive the defective genetic information. However, brittle bone disease can also develop spontaneously, i.e. through accidental mutation in the DNA, without the family having already had such a case.

Symptoms

The symptoms of the vitreous bone disease are mainly based on the instability of the bones. Patients suffer fractures very quickly, even without external force, so-called fatigue fractures. The fractures occur more frequently until the beginning of puberty and usually become less frequent in adulthood.

Frequently, large fontanelles are already conspicuous in infants. In addition, small growths and deformities of the skeleton, such as scoliosis (sideways curvature of the spine) or kyphosis (humpback formation), are also common. The musculature of the affected person is often below average. Other abnormalities include blue sclerae (what is normally white in the eye appears bluish), hearing loss, hypermobile joints, performance slumps, increased sweating and a conspicuously soft skull (rubber head). In the context of vitreous bone disease, heart valve defects such as insufficiencies (insufficient closing of the valves) or an open ventricular septum also frequently occur.