Osteopetroses are a group of rare hereditary disorders that increase the density of bones and cause bones to grow abnormally.
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These disorders occur when the body does not recycle old bone cells.
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Typical symptoms include impaired bone growth and thick bones that easily break.
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The diagnosis is based on symptoms and x-rays.
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Osteopetrosis that occurs in infancy may be fatal if not treated.
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There is no cure, but some treatments can help relieve problems caused by the disorders.
Osteopetroses result from abnormalities in certain genes. These abnormal genes are hereditary. That is, they are passed down from parent to child.
In osteopetrosis, the body does not recycle old bone cells. The
result is increased density or thickness of the bones and an alteration
in how the bones are shaped. These changes make bones weaker than
normal. The dense bone tissue also crowds out the bone marrow, which is
where blood cells are formed.
Osteopetroses range from mild to severe and can even be life
threatening. Symptoms of osteopetroses may begin in infancy (early
onset) or later in life (delayed onset).
Symptoms
Although osteopetroses comprise a range of different disorders,
many of the same symptoms develop in most of them. Bone growth is
usually impaired. Bones thicken and break easily. Formation of blood
cells may be impaired because there is less bone marrow, leading to
anemia, infection, or bleeding.
An overgrowth of bone in the skull can cause pressure in the
skull to increase; compress nerves, causing facial paralysis or loss of
vision or hearing; and can distort the face and teeth. The bones in the
fingers and feet, the long bones of the arms and legs, the spine, and
the pelvis may be affected.
Diagnosis
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X-rays
Doctors usually base the diagnosis of osteopetroses on symptoms and x-rays that show very dense or malformed bones.
When the person has no symptoms, osteopetrosis is sometimes
detected only by chance, after a doctor sees very dense bones on x-rays
taken for an unrelated purpose.
Prognosis
Early-onset osteopetrosis that is not treated with bone marrow transplantation
usually causes death during infancy or early childhood. Death usually
results from anemia, infection, or bleeding. Late-onset osteopetrosis is
often very mild.
Treatment
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Corticosteroids
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Sometimes bone marrow transplantation
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Sometimes surgery
There is no cure for osteopetrosis.
Corticosteroids, such as prednisone,
decrease the formation of new bone cells and may increase the rate of
removal of old bone cells, strengthening bones. Corticosteroids may also
help relieve bone pain and improve muscle strength. Bone marrow transplantation seems to have cured some infants with early-onset disease. However, the long-term prognosis after transplantation is unknown.
Fractures, anemia, bleeding, and infection require treatment.
If nerves going through the skull are compressed, surgery may be
required to take pressure off the nerves. Surgery may also be needed to
relieve increased pressure in the skull. Orthodontic treatment may be
needed to correct distorted teeth. Plastic surgery may be done to
correct severe deformities of the face and jaw.
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