A Simple Guide to Osteogenesis Imperfecta

A Simple Guide to Osteogenesis Imperfecta
--------------------------------------------

What is Osteogenesis Imperfecta(also known as Brittle Bones)?
---------------------------------------------------------------------

Osteogenesis imperfecta (OI) is an inherited disorder of the connective tissue resulting in imperfect bone formation and hence causing fractures in childhood.
It also causes fractures in adults.

Who is at risk of Osteogenesis Imperfecta?
-----------------------------------------------

Osteogenesis Imperfecta is a congenital condition affecting 2 forms of genetic disorder:
1.autosomal dominant - usually milder with frequent fractures

2.autosomal recessive - usually more severe and can lead to early death

Therefore there is always a family history of fractures of children in the family.

usually resulting from abnormalities of the genes that control the production of a protein called ; it has nothing to do with the calcium part of bone, which is what shows up on X-rays


What causes Osteogenesis Imperfecta?
----------------------------------

Osteogenesis Imperfecta is a condition resulting from impaired maturation of the collagen fibres or synthesis of abnormal collagen.

Collagen is the main protein in bone and is necessary for the bone to form strong bone matrix.
The abnormal collagen results in soft fragile bones, ligamentous laxity and thin sclera.

In the autosomal dominant form of Osteogenesis Imperfecta, the condition can be passed from one generation to the next.

Sometime the cause is a new genetic mutation which results in the Osteogenesis Imperfecta.
There is no previous history of Osteogenesis Imperfecta.
This has been seen in IVF of frozen egg from mothers trying for a pregnancy.


What are the symptoms of Osteogenesis Imperfecta?
-------------------------------------------------

Symptoms:
---------------

1.fractures is the most common symptom especially in newborns.
Multiple fractures may occur easily in the newborns and pose a danger to life.
As the child grow older the risk of fractures decreases especially after puberty.

2.lax joints

3.eyes conjunctiva(white)may be blue or grey.

4.teeth may be discoloured and fragile.

5.increased liability to bruising due to the abnormal collagen in the lining of small blood vessels.

6.Deafness is due to problems in the small bones in the middle ear which may be fractured or deformed so that sound waves cannot be transmitted easily to the inner ear

7.Hernias are due to poor formation of collagen fibres or abnormal collagen in the muscles.

8.Excessive sweating or intolerance of heat - the cause of this is unknown.

9.Dwarfism and structural abnormalities may occur due to basic defect and frequent fractures

10.Mental development is not affected

How do you made the diagnosis of Osteogenesis Imperfecta?
-------------------------------------------------

Diagnosis of Osteogenesis Imperfecta is often based on
1. history and pattern of fractures

2. blue or gray whites of the eyes.

3.X-rays in severe cases -shows previous fractures and deformities
The bones may appear demineralised .

4.wormian bones are additional small bones seen in the sutures between the scalp bones.
They occur in 50% cases of Osteogenesis Imperfecta.

5.Specialised test for diagnosis of Osteogenesis Imperfecta involve taking a small piece of skin, culturing the cells and chemically examining the collagen produced.

6.Another specialized test uses a blood sample to search for mutations of the genes coding for the collagen of bone.


What are the complications of Osteogenesis Imperfecta?
-------------------------------------------------------

The complications of Osteogenesis Imperfecta are:

1. multiple frequent fractures of the bone,

2. deformities of the bone and body

3. death in newborns from multiple fractures


What is the treatment of Osteogenesis Imperfecta?
-------------------------------------------------------

1.Good treatment of fractures to make sure that the bones healed without deformities.
Immobilization of fractures can lead to the loss of bone so early mobilization of the patient is important.

2.Surgical use of fixed or telescopic metal rods inserted into the shafts of bones can prevent appreciable deformity.

3.occupational therapy is important in preventing falls especially with handrails and other adaptation to the home.

4.no drug treatment including growth hormone have been effective.
Various bisphosphonate drugs trials are in progress.
There has encouraging evidence of their effectiveness in some patients.

5.Women with Osteogenesis Imperfecta may try Hormone Replacement Therapy(HRT) at menopause since HRT has been know to improve the bone structure and also prevent heart attacks.
However there is a very small risk of breast cancer.

In the case of Osteogenesis Imperfecta ,the advantages of HRT may be greater than the disadvantages as the chances of fractures is higher after the menopause.

6.Stopping smoking is important because smoking diminishes the bone by up to 5 per cent, thus increasing the risk of fractures.


What is the prognosis of Osteogenesis Imperfecta?
----------------------------------------

Prognosis depends on the severity of Osteogenesis Imperfecta.

In very severe cases, death within several years

In less severe cases, multiple and frequent fractures may occur followed by deformities.