Osteogenesis Imperfecta
Description:
Osteogenesis Imperfecta (OI) is commonly called “brittle bone syndrome” because it causes bones to be come brittle and weak. This then causes the bones to break very easily, and, contrary to common belief, is not caused by malnutrition. A person with OI is affected throughout life by a range of symptoms from muscle weakness to scoliosis (curved spine). Also, there are eight different types of OI, each having different ranges of severity, from mild to lethal, as well as having any combination of symptoms. Furthermore, depending on which type a person has depends on how they inherited it, some types are autosomal dominate others are autosomal recessive and still others are mutations.

Inheritance:
Depending on the type of Osteogenesis Imperfecta a person has depends on how it was inherited. Most commonly, OI is inherited in an autosomal dominate pattern. This means that it only takes one bad chromosome to give an offspring the dieses; however, usually these types are the less sever. Also, other types of OI can be autosomal recessive meaning that two bad chromosomes are needed to have the dieses and if there is only one bad chromosome the offspring will be a carrier for the dieses. Few types are recessive and therefore it is rare to have an autosomal recessive type of Osteogenesis Imperfecta. On the other hand, many types of OI are mutations. These mutations are spontaneous it has not been yet identified on which chromosome the mutation occurs. Furthermore, 35% of OI patients are born into families with no history of OI. If a person has a spontaneous type of OI, all of their children will be carriers of the dieses.

Symptoms:
The symptoms of an OI patient vary depending on the type that they have.
· Muscle weakness
· Fatigue
· Easily bruised
· Short stature
· High-pitched voice
· Multiple fractures
· Joint laxity
· Hearing loss
· Bone deformities
· Curved bones
· Blue tints to the whites of eyes
· Breathing problems
· Dentinogenesis Imperfecta (brittle teeth)
· Restrictive Pulmonary dieses
· Scoliosis
· Death

Daily Life:


Diagnosis:
Osteogenesis Imperfecta is usually diagnosed in normal examinations done by a doctor. If this happens a specialist should be consulted. Sometimes skin biopsies and chronic villas sampling can diagnose the dieses as well. Also, wile still pregnant an amniotic fluid test can be done to find abnormalities. In extreme cases, fractures can be seen in the womb. DNA tests, bone density scans, and genetic testing can all be used to confirm a diagnosis. Many mild cases of OI never get diagnosed because few symptoms show. There are different types of OI and not all types can be diagnosed or confirmed with all the same tests.

Treatment:
Treatments for OI are directed toward controlling symptoms wile increasing mobility and bone and muscle strength. Treatments vary on the type of OI a person has. All OI patients should have regular check ups with both the family doctor and an OI specialist. Physical therapy and exercise should be done on a weekly to daily bases. Braces to support joints and mobility aids (canes walkers, ext.) should be used if needed. Casts and splints are used to set broken bones. To strengthen bones medications are used or a patient can get surgically implanted metal rods. Keeping a healthy weight and nutrition is essential for OI patients, also things like smoking and excessive amounts of alcohol or caffeine should be avoided. There is no cure for Osteogenesis Imperfecta.


Research:
There are ongoing studies on the effects of an increased intake of vitamin D and different nutritional studies on children ages 2-10. Also, some tests are being conducted using different combinations of growth hormones. These are attempts to control and suppress various symptoms of OI. Some experts even say there is a potential for gene therapy in the future. Although there is research being done it is unclear if these new treatments will be affective on any or all of the eight types of OI. Also, there are studies on the life expectancy of patience with the different types of OI and what it is that causes the mutations in seemingly healthy genes.



Additional Facts:
Although evidence shows that Osteogenesis Imperfecta goes back to ancient Egypt in 1000 BC it was in 1849 that W. Vrolik named the dieses and the 1970’s that Dr. David Sillence started categorizing the different types of OI. Lifespans range from the time of birth to a normal lifespan. The fallowing is a simple and quick overview of the different types of Osteogenesis Imperfecta:
Type I is the most common and least severe of all the types. It has few, mild symptoms and is inherited in an autosomal dominate pattern.
Type II is the most severe of all the types. Infants born with this type do not live past a few weeks after birth and is caused by a mutation.
Type III is the most harmful to children. Harsh symptoms fade over time but fully grown those with this type do not grow over 3’6” and is caused by a mutation.
Type IV is a moderate type. This is the second most common type and is autosomal dominate.
Type V is a moderate case, as well. It represents 5% of all the OI cases diagnosed, is autosomal dominate, and differs from type IV because it shows less symptoms.
Type VI is the rarest of all the types. Being so rare it is not certain exactly how it is inherited, but it is moderate.
Type VII is very similar to types IV and II. This type causes a lack of a cartilage-like protein in the body and is a mutation.
Type VIII is similar to types II and III. This type causes an extremely short stature and is a mutation.
Every 6 to 7 per 100,000 people worldwide have Osteogenesis Imperfecta and 4 to 5 of these people have either type I or IV.






Punnett Square:


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Pedigree Chart:


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Pictures:
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Resources:

Osteogenesis Imperfecta Fundation
http://www.oif.org/site/PageServer?pagename=AOI_Types
eMed TV’s page on symptoms
http://bones.emedtv.com/osteogenesis-imperfecta/types-of-osteogenesis-imperfecta.html
Osteogenesis Imperfecta article by Dr. Guillaume Chevrel
http://www.orpha.net/data/patho/GB/uk-OI.pdf