Marble disease: symptoms and treatment
Marble disease ( congenital osteosclerosis, osteopetrosis) is a very rare hereditary disease in which the skeleton and bone marrow of a child or adolescent is affected.Patients become fragile bones, the hematopoiesis system ceases to function fully.
Depending on the timing of the onset of the first symptoms of the disease and the nature of these symptoms, congenital osteosclerosis is divided into early and late. The early form of marble disease develops in children of the first year of life and proceeds very hard, therefore it is also called malignant.In turn, late form , which occurs more often in adolescence, is accompanied by less pronounced pathological changes from both the skeleton and the hematopoiesis system.Such patients have various health problems, but overall the prognosis for their life is favorable.Table of Contents: Causes of Marble Disease Mechanisms for the Development of Marble Disease Symptoms of Marble Disease Diagnosis Treatment Principles
Causes of Marble Disease
Marble disease is a hereditary pathology of .Scientists managed to find three genes responsible for the development of congenital osteosclerosis.It is these genes that encode proteins that are necessary for the proper functioning of osteoclasts and osteoblasts, the cells on which the condition of bone tissue depends.If a mutation occurs in one of these genes, a marble disease can develop in the offspring.
The malignant form of the considered ailment is transmitted by the autosomal recessive type .That is, to make the child sick, mutated genes should be in both parents.This feature of the inheritance of marble disease explains the fact that in some isolated ethnic groups where there are many closely related marriages, the number of cases of this disease is significantly higher than in the population.
The late form of marble disease, on the contrary, has an autosomal dominant type of transmission of , so it meets more often( a mutated gene can only be found in one of the parents).
People who have cases of marble disease in the family can undergo a special diagnosis that identifies altered genes.This will allow to predict whether there will be health problems for future children.
Mechanisms for the development of marble disease
The basis of this pathology is the imbalance between the formation and resorption( resorption) of bone tissue.There is such a violation due to a decrease in the number of osteoclasts( cells responsible for bone resorption) or their incorrect functioning.
Due to imbalance, the bone tissue becomes denser and becomes redundant, but this does not mean that its strength increases.Conversely, in marbled disease, the bones lose their elasticity and become brittle. In addition, with osteosclerosis, the intraosseous cavity of the tubular bones and the spongy substance of the flat bones is replaced by a connective tissue.That is, where the bone marrow should normally be, sclerotic cells appear.This leads to a disruption in the functioning of the hematopoietic system.
In general, all these pathological changes cause the appearance of skeletal deformities, fractures, anemia, hemorrhagic diathesis, and various neurological disorders in patients.
Symptoms of marble disease
The clinical picture of marble disease is polymorphic.In patients, as a rule, there are symptoms of defeat of the musculoskeletal system, hematopoietic and nervous system.
The main symptom of marble disease is pathological fractures. Pathological they are called because they occur with minimal injuries and large large bones( most often on the femoral).After a fracture, osteomyelitis may develop( this is one of the most formidable complications of marble disease).
In addition to fractures, the doctor can detect various deformations of the skeleton( O-shaped legs, a disproportionate skull, pathological changes on the side of the spine) when examining patients.As a result of deforming and changing the structure of the bones, patients have pain when walking in the legs and back.
The defeat of the hematopoiesis system with a marble disease is manifested by symptoms of anemia: pallor, weakness. In response to the insufficiency of the hematopoietic function of the bone marrow, the liver, spleen, lymph nodes increase, the immune defense of the body weakens, hemorrhagic diathesis develops.
The appearance of neurological disorders in congenital osteosclerosis is associated with the compaction of the bones of the skull and a decrease in the size of the anatomical openings through which the nerves pass( due to such changes, the nerves compress).Therefore, peripheral paresis and paralysis of , with vision can occur in patients.When filling the bone tissue of the bone labyrinth of the inner ear , the development of deafness is possible. In addition, due to deformities of the skull, patients may suffer from hydrocephalus.
In general, the patients with marble disease of children are characterized by a lag in physical development, various problems with teething, massive lesions of the dentition with caries.
With late forms of marble disease, the clinical picture is usually smoothed, there are no pronounced neurological manifestations, deformations of the skeleton.The idea of osteosclerosis of doctors can only be prompted by repeated pathological fractures.
To confirm the diagnosis, doctors are assisted by X-ray methods of the study.All the bones of the skeleton are sealed on X-rays of the patients( they are not transparent to X-rays), there is no bone marrow channel in the tubular bones, there is a clavate thickening of the humeral and femur bones.
When examining patients' blood, signs of anemia and an increase in some biochemical indicators( acid phosphatase activity, etc.) are found.In the analysis of urine changes, as a rule, there is no( this distinguishes osteosclerosis from destructive bone diseases, in which the resorption of bone tissue predominates over its formation).
For a more detailed study of the health status of patients, it is necessary to consult a neurologist, hematologist, ophthalmologist, otolaryngologist, dentist .Different genetic studies may also be required.
Principles of treatment
To date, there are no methods that completely cure marble disease. This is due primarily to the fact that this pathology is very rare and doctors simply do not have sufficient clinical experience in dealing with it.Therefore, while the most effective in marble disease is considered bone marrow transplant .With the help of transplantation, you can try to restore the process of bone resorption and hematopoiesis in the patient's body.This technique is used in malignant recessive forms of the disease.In addition, various regimens for the treatment of congenital osteosclerosis with interferon and calcitriol( vitamin D) are developed and tested.
In the late manifestation of marble disease, doctors use various therapeutic measures to maintain the bone and nervous system, as well as to improve overall patient health.The patients are shown both drug therapy and exercise therapy, swimming, massage, special diet, spa treatment.If necessary, an orthopedic correction of skeletal deformities is performed.
It is very important for patients with marble disease to be protected from injuries, as this is fraught with the development of fractures and osteomyelitis.In addition, dynamic follow-up is required for the orthopedist, dentist and other specialists.
Zubkova Olga Sergeevna, medical reviewer, epidemiologist doctor