Imperfect Bone Formation

This disease belongs to the group of diaphyseal dysplasia of the bone system. Typical signs of imperfect bone formation are frequent fractures. Upon closer examination of such a person, one can note the blue-gray color of the sclera of the eyeballs. Another characteristic manifestation is the early development of deafness. Two forms of this disease are described in the literature: congenital and late. In the first case, during the period of intrauterine development of the child, numerous fractures of bones already occur, which leads to a pronounced deformation of the lower limbs at birth. In the second case, fractures appear somewhat later. As with that, and with another form, you can note the gray-blue color of the sclera. In these children, the fontanelles are closed late, sometimes the bones of the skull in newborns are soft. Teeth often have an amber color, late eruptions, are often amazed with caries. As a rule, there are fractures of long tubular bones( thigh, shoulder, bones of the shank and forearm) and spine. Fractures of the bones of the skull, pelvis, phalanx of fingers and feet do not occur. Deformities of the extremities can be expressed very strongly, and the number of fractures does not depend on the form of the disease.

According to the literature, deafness develops quite early - at the age of 20-30 years. Changes that are detected by radiographic examination of the osseous system depend on the severity of the course of the disease. The main sign of imperfect bone formation is the widespread osteoporosis of the entire skeleton. After a fracture around the bone, periosteal( periosteal) calluses are formed, surrounding the fracturing fracture. The sizes of these calluses sometimes are huge, in some cases mistakenly mistaken for a tumor of bone tissue( pseudo-sarcoma).In the spine, there is a different degree of expression of platiphondilia, the vertebrae acquire a biconcave form. The seams of the skull are enlarged, they contain a large number of inserted ossicles.

In 1979, another division of imperfect education was suggested, according to which IV types of disease are distinguished.

I type is transmitted by the dominant type of inheritance. In such children, blue color of sclera can be noted, ear hypostasis develops early, bone changes are moderately expressed.

II type is transmitted by autosomal recessive type of inheritance and ends with intrauterine fetal death.

III type of imperfect bone formation is transmitted by an autosomal recessive type of inheritance, proceeds with severe progressive bone deformities, the color of the sclera remains normal, there is a violation of dentition.

IV type is transmitted by a dominant type of inheritance, sclera retains normal color, and the remaining manifestations can vary widely. Parents who have one of the above signs of the disease or a combination of them, but who do not suffer from increased fragility of the bones, children with different, including severe forms of defeat of the musculoskeletal system, may be born. This circumstance is also taken into account when conducting medical genetic counseling for such families.

Cranio-clavicular dysplasia has been known for a long time. The most characteristic changes are observed in the skull and collarbones, which was the basis for creating the name of the disease. The signs of the disease are clearly revealed even at the time of the birth of a sick child. Children with pronounced signs of the disease may show increased softness of the bones of the skull, in less pronounced cases, attention is drawn to the large size of the fontanelle, which in front reaches the frontal bones and connects to the small fontanel at the back, often with a discordance of the frontal bones. The spring camp closes very late, and in some cases remains in adulthood. The main symptom of craniocerebral dysplasia is the underdevelopment of the clavicles. Complete absence of clavicles is rare( in 10% of cases), more often one of the ends of this bone is missing.

A characteristic manifestation of such a violation in the structure of the skeleton is unusual mobility in the shoulder joints - the child can bring the shoulders in front of him until they come into contact with each other. In some cases, children have scoliosis, short distal phalanges of the fingers and underdevelopment of the nails. Very characteristic is a belated and imperfect development of permanent teeth. Milk teeth can remain up to 25-30 years of age, in connection with which such an individual can form an excessive number of teeth. Radiographic examination of the bone system clearly reveals a defect in the development of clavicles. They either consist of separate fragments( one or two), or they may be completely absent. The share of recent cases accounts for only 10% of cases. The defeat of these bones of the human skeleton is mostly bilateral and asymmetric.

Changes in the pelvis and hip joints are also characteristic. The head of the femur has large, in comparison with the norm, dimensions, a rounded shape. Radiologic examination of the spine shows an anomaly in the development of one or more vertebrae, and any part of the spinal column can be affected. Cranio-clavicular dysplasia is transmitted by an autosomal dominant type of inheritance.