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7/29/2019 Osteogenesis Imperfecta(1)
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Meaning: imperfect bone formation
Also Known As:
Brittle Bone Disease
Brittle Bone Syndrome
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How Common is it?A range of 25,000 to
50,000 Americans
are affected by OI.This wide range is
due to the fact that
very mild cases ofOI often go
unnoticed and are
not diagnosed.
Worldwide, about 1
in every 20,000
people have OI.Generally, it is a
rare disease.
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Q: WHAT IS OSTEOGENESIS IMPERFECTA?A: OI is a genetic disorder
the affects the gene that
produces collagen in your
body. Collagen is a
protein that connects
tissues in your body. It
also helps with the
formation of teeth,
ligaments, and sclera
(white outer tissue of the
eyeball).
SYMPTOMS:
multiple, frequent fractures
muscle weakness
joint laxity
curved bones
Scoliosis
brittle teeth
short stature
blue sclera
fragile skin
triangular head and face shape
respiratory complications
By looking at a person, you MAY be
able to tell if they had OI by their
abnormally small stature, the whites of
their eyes being a blue color, theywould have a triangular head shape,
and could potentially be using a
walker, wheelchair, or have casts on at
the time. However, some people with
OI have relatively mild symptoms and
you MAY NOT notice that they lookdifferent in any way.
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WHO?
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HowdoesOI
affecta personslife?BasedonthetypeofOI,apersonslifespancouldbeaffectedverylittle,whileitcanalsobedrasticallyaffected.Thereare8
differenttypesofOI.SimilarsymptomsmayoccurinalltypesofOIwithvaryingseverity.
Differentsymptomsmayalsoshow
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HowdoesOIaffectaCONTINUED
TYPE I: mildest and most common form of disorder; doesnot usually affect lifespan unless a severely traumatic event
occurs; most fractures occur during youth and adolescence
TYPES II and III: most severe types; infants with TYPE II
commonly die during pregnancy or shortly after birth ,
however some with TYPE III may survive longer but withmany disabilities and traumatic events
TYPES IV-VII: moderate forms of disease; lifespan not
dramatically affected; more rare than type I and deal with
different genes
TYPE VIII: more severe type similar to types II or III butsome symptoms vary
*There is no certain reduced life expectancy, but with more
severe cases of OI the probability of death from accidental
trauma or respiratory complications is highly increased.
-Respiratory problems and accidental trauma arethe most common deaths of people who have OI.
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Can a person be tested forOI? How is OI treated?
YES. Testing can take place tomake a diagnosis if a personis showing symptoms of OI.Tests can also be planned forchildren whose families havebeen affected by OI. Testing
and diagnosis is usually doneduring childhood, and adiagnosis can sometimes bemade during pregnancy.
Methods of testing include:
o X-Rays
o DNA sequencing using a collagen
sample from blood
o Biochemical tests using a
collagen sample from the skin
o tests during pregnancy can be
done through ultrasound andamniocentesis
There is no cure for OI as of rightnow. However, there are someways of dealing with the disorder.Biophosphonates and othermedicines are used to make bonesstronger and more dense, andsurgically placing rods in thebones of the legs often helpprevent major fractures. There areminor symptoms of thebiophosphonates, including
stomach upset and heartburn. Ona regular basis, doctors andfamilies focus on mobility andsafe exercise such as swimmingand physical therapy, as well askeeping fracture numbers to aminimum. Braces, wheelchairs,
and casts are useful aids as well.
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Support Groups
The OsteogenesisImperfecta Foundation
is a major organizationthat helps educatepeople about OI. It alsogives reference to
several people whomyou can contact aboutlocal support groupsnear you.
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35% of OI cases are aresult of spontaneous
mutations, while the
others come from
parents affected by OI
or parents who are
carriers.
Inheritance Patterns and Gene Location
Dominant or Recessive?
About 85%-90% of OI
cases that are inheritedare inherited in dominant
manner. There are some
rare instances where the
disorder is recessive an
autosomal however. The
different inheritancepatterns may also deal
with slightly different
genes.
The mutations that
cause collagen
problems can affect
either the quantityof
collagen or the
qualityof the
collagen produced.
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Inheritance Patterns and Gene LocationContinued
The gene for Osteogenesis
Imperfecta is located on
chromosome 17 which has 81
million base pairs.
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INTERESTING FACTS
*Parents of childrenwith OI are often
accused of child
abuse, which is why
they are advisedalways to carry a
document stating
their childs
condition so that
their kids arent
taken from them at
any point.
*OI does not affect
fertility.
*OI was
recognized in anEgyptian mummy
that is dated
back to 1000 BC.
*The 2 forms of OIthat are inherited
recessively were
discovered only 4
year ago.
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oif.org
genome.gov
orthoinfo.aaos.org
Dnarss.com
Ghr.nlm.nih.gov