|
Osteogenesis imperfecta (OI) is a group of genetic
bone disorder. It is characterized by bones that break easily often from little
or no apparent cause. It is caused by a genetic defect that affects the body’s
production of type I collagen. Collagen is the major protein in the body’s
connective tissue which provides support and structure to the bones. People with OI either have less than normal collagen or the quality of collagen is poorer
than normal leading to weak bones that fracture easily. OI is caused by a
dominant genetic defect. While some inherit the disorder from a parent, there
are others who get this when the genetic defect occurs as a spontaneous
mutation.
There are four types of this disorder with symptoms
ranging from mild to severe:
Type I In this classification,
the quality of collagen is normal but there is not enough:
Type II
In this type, both the quality and quantity of collagen is poor:
-
Severe respiratory problems due to underdeveloped
lungs
-
Severe bone deformity and small stature
-
Most patients with this type of OI die within the
first year of life due to respiratory failure or intracerebral hemorrhage
Type III
In this type, the quality of collagen is poor:
-
Bones fracture easily
-
Bone deformity
-
Respiratory problems
-
Short stature, spinal curvature and barrel-shaped
rib cage
-
Loose joints
-
Poor muscle tone in arms and legs
-
Discoloration of the whites of the eyes
-
Early loss of hearing
|
|
Type IV
The quality of collagen is poor:
-
Bones fracture easily especially before
puberty
-
Short stature, spinal curvature and
barrel-shaped rib cage
-
Bone deformity is mild to moderate
-
Discoloration of the whites of the eyes
-
Early loss of hearing
Treatment
There is no cure for OI. Treatments focuses on increasing overall bone
strength and preventing fracture and maintain mobility.
Physiotherapy Physiotherapy
is used to strengthen muscles and improve motility minimizing the risk
of fracture.
Physical aids Use of
wheelchairs, braces, and other mobility aids helps many individuals
with OI achieve a significant degree of independence and control over
their lives.
Bisphosphonates
Bisphosphonates are used to increase bone mass and reduce the
incidence of fracture. It can be either through oral doses or
intravenous injections.
Surgery The options for
surgery include inserting metal rods along the long bones to improve
strength, spinal fusion to correct scoliosis and surgery for basilar
impressions. None of these options are without complications.
Genetic counseling As OI is
a genetic disease, counseling can help patients and their family
members understand OI genetics and the possibility of recurrence, and
assist in prenatal diagnosis for those who wish to exercise that
option. |
