Symptoms of osteoarthritis are dysfunctions of the osteoarticular, vascular, eyes, hearing, nervous and masticatory systems. The cause of the disease is a disturbance in the formation of type I collagen, which is a building component of the skin, bones, teeth, tendons and blood vessel walls. Find out how to recognize the symptoms of osteogenesis imperfecta.

Congenital bone fragility( osteogenesis imperfecta hereditaria , abbreviated as OI) is a genetically determined disease of the connective tissue. It is caused by quantitative and / or qualitative disturbances in the production of type I collagen - the building protein of teeth, sclera, connective tissue of the skin, bones, tendons, ligaments and blood vessel walls. This process leads to abnormalities in the structure of the osteoarticular and vascular systems, eyesight, hearing and chewing organs, and consequently to their dysfunction.

Congenital fragility of the boneis a rare disease with an estimated incidence of 1 in 10,000-30,000 cases.

Congenital fragility of the bones - types of the disease

  • type I - the most common (about 60% of cases) and the mildest form of the disease;
  • type II - the most severe form of the disease. It is often the cause of miscarriage or fetal death;
  • type III - symptoms similar to type I, but much more severe;
  • type IV - it is characterized by the greatest diversity and includes all cases that do not correspond to types I, II or III.

    Recent studies distinguish 3 other typesosteogenesis imperfecta : V, VI and VII.

    Congenital fragility of the bones - symptoms

    The symptoms of congenital fragilityvary widely and depend on the type of disease. However, in any case, they include:

    • osteoarticular system - fragility of bones (mainly long bones and small bones of hands and feet), which occurs not only during movement, but also during rest, e.g. during sleep. In addition, ligaments excessive extensibility, generalized muscle weakness, spine and thoracic deformities, as well as osteoporosis are diagnosed;
    • vascular system - there is excessive fragility of blood vessels with symptoms of ecchymosis on the skin;
    • nervous system - headachesradiating to the neck or back of the head, trigeminal neuralgia;
    • organ of vision - blue discoloration of the sclera is observed;
    • hearing organs - hearing disorders;
    • masticatory organ - dentin development disorders (so-called dentinogenesis imperfecta). Then the teeth are discolored (usually blue-gray or yellow-brown) and transparent;
    • skin - thin, prone to bruises and scars, and to the formation of hernias.

    Congenital fragility - causes

    The cause of type I to IV bone fragility are mutations in the genes of type I collagen, which lead to a quantitative and qualitative disturbance of its production. Before collagen takes its final form, it goes through several stages of development. Disorder of any of them leads to disorders in the structure and functioning of collagen, and thus - to irregularities in the structure and functioning of various systems.

    On the other hand, types V to VII are forms of the disease conditioned by mutations in other genes or of unknown etiology.

    Congenital fragility of bones - inheritance

    Type I as well as V and VI of the disease are inherited autosomal dominantly. This means that you only need to inherit one copy of the defective gene for the disease to develop. This is because the altered copy of the gene dominates or becomes more important than the properly functioning copy. The fourth form of the disease is also inherited autosomal dominantly, but it is the so-called inheritance with variable gene penetration (in family members sharing the same pathological gene, the symptoms of the disease may be manifested to varying degrees). This is a phenomenon that makes it difficult to define the so-called genetic risk.

    Type II, III, and VII of osteogenesis imperfecta are inherited autosomal recessive, which means that defective copies of the genes must be inherited from both parents for symptoms of the disease to develop. Additionally, type II of the disease may be a new, spontaneous autosomal dominant mutation, i.e. it may appear in the child of parents who are he althy and have no defective genes.

    Congenital bone fragility - diagnosis

    Congenital fragility of the bonescan be detected already during pregnancy, during ultrasound examination. After the 13th week of pregnancy, you can test for the presence of genetic markers and take the chorion to assess the structure of collagen. After the baby is born, the disease is diagnosed on the basis of collagen biochemical tests and genetic tests.

    Good to know: Prenatal testing: what is it and when to do it?

    Congenital fragility of the bones - rehabilitation

    The basis of treatment is rehabilitation,the purpose of which is to counteract frequent fractures that lead to significant bone deformation. It consists of exercises that improve muscle strength, correct posture and teach you to keep your balance, as well as massages. A form of rehabilitation that is liked by children is especially water exercises and hydro massages.

    Congenital fragility of the bones - treatment

    Treatment for osteogenesis imperfecta can vary. We distinguish, among others surgical and pharmacological treatment, as well as gene or stem cell therapy.

    Congenital bone fragility - surgical treatment

    Surgical correction of skeletal deformities is carried out, among others, by with the help of metal wires or rods that support defective bones. In young children, you can also use telescopic rods, which grow with their development.

    Congenital bone fragility - drug treatment

    Drug treatment is primarily based on administering bisphosphonates to patients. These are drugs that bind to bones, improve their mineralization and inhibit the action of cells responsible for bone deformation, and thus - reduce the frequency of fractures. However, bisphosphonate therapy has side effects, such as inhibition of bone mass turnover and poorer bone tissue remodeling, associated with impaired healing of microdamages and fractures. In addition, pharmacotherapy uses sex hormones, magnesium s alts, vitamin C, vitamin D3, calcium s alts and salmon calcitonin.

    Congenital fragility of bones - stem cell therapy

    Stem cells can give rise to various types of tissue, such as bone, cartilage, adipose tissue, muscle, and tendons. For osteogenesis imperfecta, cell therapy involves the transplant of stem cells from the bone marrow of a he althy donor, which can either turn into osteoblasts (bone-forming cells) or that can replace the recipient's defective osteoblasts with normal donor stem cells.

    Congenital fragility of bones - gene therapy

    The goal of gene therapy is to replace a defective collagen gene with a gene that works properly. However, research on this method is still ongoing.

    Congenital fragility of the bones - symptoms. Type I

    Type Iosteogenesis imperfectais the most common and mildest type of the disease and is characterized by:

    • correct height;
    • a small number of fractures (around 10-15), with the first fractures appearing rather late;
    • fractures heal properly ( although deformities appear in about 15 percent);
    • ligament laxity;
    • incorrect structure of the lower limbs:curvature of the lower limbs, knee valgus, metatarsal varus;
    • kyphoscoliosis (curvature of the spine backwards and to the side) in adults;
    • blue sclera;
    • early conductive hearing loss.

    Two subtypes have been distinguished: IA, in which the teeth are of normal structure, and IB, in which the dentinogenesis imperfecta features are found. there is no advanced osteoporosis. This type ofosteogenesis imperfectadoes not substantially affect life expectancy. Spontaneous improvement of the patient's condition is observed in adolescence.

    Congenital fragility of the bones - symptoms. Type II

    Type IIosteogenesis imperfectais the most severe form of the disease. It often leads to a miscarriage or death of the fetus. However, if a child is born, it states:

    • a very large number of fractures that are difficult to determine (they occur during fetal life or shortly after birth);
    • soft bones of the skull vault;
    • triangular face;
    • narrow chest;
    • short, deformed limbs;

    The death of a child as a result of cardiovascular and respiratory complications usually occurs within a year after birth.

    Congenital fragility of the bones - symptoms. Type III

    • very short stature (sometimes stunted);
    • a very large number of fractures (about 100 or even more). They can happen in utero. In turn, after birth, they always appear in the first year of life;
    • deformities of the spine (most often lateral curvature), caused by numerous fractures and fractures of the vertebrae;
    • progressive osteopenia, deepening skeletal deformities;
    • severe muscle weakness. The sick person cannot walk, rides in a wheelchair or lies in bed;
    • tooth development disorders;
    • blue sclera with a tendency to brighten.

    Hearing disorders are not diagnosed in this type of disease. Life expectancy and quality are closely related to the course of the disease, with the highest mortality occurring before the age of 10.

    Congenital fragility of the bones - symptoms. Type IV

    Type IVof osteogenesis imperfectacharacterizes the variability of the course of fracture frequency, age of first symptoms, severity of bone deformities independent of fractures. Only short stature is characteristic. In addition, the sclera is normal or blue at birth and tends to brighten. Rarely, conductive hearing loss is diagnosed.

    Congenital fragility of the bones - symptoms. Type V, VI and VII

    Callus overgrowth is characteristic for type Vfracture site. In turn, the symptoms of type VI are similar to those of type IV. Type VII, on the other hand, presents with osteopenia (a condition where bone mineral density is lower than normal), blue sclera, and frequent deformities and fractures early in life.

    Category:

    Spine, bones, joints