Marble Bone Disease

introduction

Our bone and skeletal system is not a rigid structure and is naturally subject to a constant process of transformation.

Bone substance is regularly made up of special cells, the so-called Osteoclasts, and, in turn, by the, as Osteoblasts designated cells rebuilt. Structural damage to the bone, caused by everyday movements and loads, is repaired as quickly as possible by the body's own cells and the fine structure of the bone is adapted to the respective stresses from the environment. This gives our skeletal system a distinctive stability and functionality.

If there are disturbances in the area of ​​the cells that break down and build up the bone, the bone system suffers losses in terms of its strength and resistance: it becomes brittle and unstable.

In marble bone disease, also medicinally as Osteopetrosis or Albers-Schönberg syndrome called, it is a rare hereditary disease. The above-mentioned bone-degrading cells, the Osteoclasts. The modeling of the bone system is disturbed and the balance is shifted in favor of the cells that build up the bone.

Due to the lack of activity in bone resorption, marble bone disease leads to an increased accumulation of bone substance in the body. This accumulation has a pathological character, because it causes a disruption of the bone architecture, i.e. the fine structure of the bones, and thus a reduced stability of our skeletal system.

The remodeling processes even go so far that the bone marrow, which fills the inner spaces of the bones and embodies an important part of our blood formation and immune system, is replaced by bone substance.

causes

The exact Cause of marble bone disease is still unknown today. She is one Malfunction of the bone-degrading cells based on which by genetic changes of the genetic material of these cells.

It will two big forms of marble bone disease:

1. On the one hand there is autosomal dominant inherited form. Autosomal dominant describes a form of inheritance in which a broken link on the gene carrier of our body, the chromosome, is sufficient to cause a characteristic expression of the marble bone disease. This form usually only manifests itself during the growth spurt around the age of maturity 12 to 20 years.
2. The autosomal recessive form from (here must both limbs a whole Pair of chromosomes be defective) that already early childhood aged one to two years causes a severe form of marble bone disease. If left untreated, the second form has a very poor prognosis and can lead to Death in early childhood to lead.

Symptoms

In the Marble Bone Disease it occurs due to the disturbed bone structure Instability of the bone with an increased Susceptibility to Broken bones. Theirs are characteristic of these breaks poor healing tendencyso that there is a permanent limitation of stability in the skeletal system, respectively recurring breaks can come.

Bone pain may also occur.

The marble bone disease also causes one Bone augmentation, due to the lack of degradation, especially in the area of ​​the skull bone. The overgrowth of bones in the face leads to Narrowing, the cranial nerves running there.In this way, parts of the nerves that are responsible for our facial muscles or for the perception of our hearing and sense of balance can be pinched off. The consequence would be a lack of expression in the representation of emotions by the paralyzed Facial muscles, hearing loss and dizziness. At compression of In the worst case scenario, marble bone disease can lead to blindness due to the optic nerve.

The Remodeling processes within the bone even extend so far that the bone marrow, which the Interiors of bones fills in and an important part of our Blood formation- and Defense system embodied, is replaced by bone substance. As a result of decreasing bone marrow spaces, stimulates marble bone disease, the so-called disease that occurs outside the bone marrow extramedullary blood formation in the liver and spleen. This form of blood formation takes place naturally in the unborn child in the womb instead of, but stands for one after the birth pathological process. A enlarged liver such as spleen thus also belong to the picture of marble bone disease.

Since the cells of our blood system are also assigned a defense function during disease processes, it occurs as a result of impaired blood formation to a weakened immune system With increased susceptibility to infections.

The most important mineral for building up our skeletal system is calcium. The marble bone disease consumes the Calcium reserves our body and uses it to build up bone substance, if it is not broken down. Through the lack of concentration of calcium in the blood, it can become a increased excitability of the muscles that come in the form of Seizures can appear.

Ultimately, the Severity of symptoms in marble disease vary greatly, depending on which form, i.e. the somewhat milder autosomal dominant or the mostly poorly progressing autosomal recessive form of the disease is present.

Diagnosis

Whether it is a Marble Bone Disease your doctor will on the one hand through targeted questioning about your complaints, such as frequent badly healing broken bones make, on the other hand, the suspected diagnosis imaging procedureshow x-rays corroborate their skeletal system.

Because in the pictorial representation of the bone structure typical characteristics recognize marble bone disease. One is indicative in the x-ray visible three-layer the Vertebral bodies, the so-called Sandwich vortex. In addition, a strong compression and Hardening of the bone architecture read from the pictures. Another characteristic that gave the marble bone disease its name is that in the X-ray typical striations of the long tubular bones, like thigh or humerus bones that make it appear marble-like.

Blood tests will also be carried out. Here can those who are distinguished for the marble disease decreased calcium concentration in the blood and a Drop in blood cellsdue to the impaired blood formation.

Because of the weakened immune system, Affected people show up more often ill and limp.

In rare cases it will take local anesthesia a so-called Bone marrow aspiration performed to assess blood formation and disease spread in the bone.

Therapy and prognosis

A treatment The triggering cause of marble bone disease is currently still not possible. Glucocorticoids can be prescribed symptomatically. They are among the steroid hormones and perform a wide range of tasks in our body. They are used therapeutically here Inhibiting inflammatory processes with drugs.

Furthermore, so-called interferons are used in marble bone disease. Have these proteins protective functions with rapidly growing and proliferating tissue processes.

The therapy of first choice, which has become increasingly important in recent years and can achieve a complete normalization of the bone structure, is bone marrow transplantation. Goal is one complete renewal and a Reconstruction of the diseased bone marrow with healthy donated hematopoietic stem cells.

Has already taken place Nerve failurethat for example too blindness may have led to this, however not resolved become.