A Family Doctor's Tale - OSTEOGENESIS IMPERFECTA

DOC I HAVE OSTEOGENESIS IMPERFECTA

Osteogenesis imperfecta is also known as brittle bones disease, usually inherited.In a case of one patient with this condition it was due to genetic mutation during in-vitro fertilization.

The boy who is now about 16 years old had 5 fractures since his childhood and has been excused from national service.


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.



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.

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.

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 rsik of fractures decreases especially after puberty.

2.lax joints

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

4.teeth may be discolored 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 fibers 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



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

2. blue or grey whites of the eyes.

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

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

5.Specialized 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.

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

The treatment of Osteogenesis Imperfecta is through:


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 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.



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.