General Information / OI Types
What is Osteogenesis Imperfecta (OI)?
Osteogenesis Imperfecta (OI) is a broad group of genetic mutations that cause a defect in the way the body manufactures collagen. The general defects are the insufficient production of normal collagen and/or the production of abnormal collagen.
The most common and obvious effect is brittle bones. There are currently 4 classifications or types, with each type having a range in severity. Because most cases of OI are new genetic mutations, each person's genetic defect is slightly different. This means that each person with OI is different from each other person in regards to the specific effect this has on thier body. Some people tend to break only certain bones, while others seem to (and sometimes do) break just about everything. The severity of OI is extremely broad. The most mildly affected people may not ever break a bone or may break only a couple times in their life, while the most severely affected break hundreds of times and may die prematurely from fractures, skeletal deformities, respiratory or other complications.
Types (classifications) of OI.
This list of OI type classifications IS out of date. Several additional types have been described in the last few years.
This is generally the mildest form of
OI. People with this type may not fracture at all or may have up to a dozen or more
fractures in their lifetime. Usually fractures will be easily explainable as being
caused by sports injuries, accidents or hard falls. More severely affected
individuals with this type may fracture easily from light trauma such as a bump, light
fall or twisting/pulling motions. Often, children with this type of OI sustain
fractures that are not easily explained or not caused by obvious trauma and the parents
may sometimes be accused of child abuse. One of the distinguishing features of
people with this type of OI is that they have blue (ranging from light grey-blue to
intense blue) sclera (whites of the eyes). Most are of average or nearly average
height. Some people may have a moderate to severe hearing loss begining in thier
teens-twenties, barrel chest, scoliosis, underbite and bruise easily.
This is the severest form of OI and is
sometimes called the perinatal lethal type. Many children with this type die during
or shortly after birth. Most have many fractures at birth, deformed or bowed limbs
and hydrocephalus with evidence of healed/healing fratures before birth (seen on sonograms
and x-rays). Most will have dozens of fratures per year, with many being
spontaneous/stress fractures or from very light trauma such as from rolling over, being
picked up or sitting. Few people with this type will achieve much independance due
to the constant numerous fractures and other complications.
This type is usually fairly severe.
People with this type are generally moderately to extremely short statured, most will not
be able to walk without some type of aid and many will never be able to walk. Most
have from a few to dozens of fractures yearly which may be caused by light trauma (bumps,
twisting, falls, lifting), walking (or trying to) or may be spontaneous. Many
children will have fractures at birth and show evidence of fractures in utero. Most
will have bowed or shortened limbs and a triangular shaped head. Some people may
have blue sclera, underbite, scoliosis, large protruding (buggy) eyes, high pitched voice,
barrel chest. For many people, fractures rates drop after puberty and many people
with this type are able to become fairly independent by their teen or early adult years.
Type IV is generally moderate to
severe. Many people will be able to walk un-aided while others will need crutches or
braces to walk and some may not walk. Children may have fractures at birth and some
show signs of fractures in utero. Many will have up to a few fratures yearly, but
some people may go several months or even years between fratures, especially after
puberty. The majority of fractures are caused by mild to moderate trauma, but there
may be some spontaneous fractures. Many children have fractures of a type that is
common with child abuse (spiral fracture) leading parents to become suspected of child
abuse in some cases. Many people will be slightly to moderately short statured and
may have short or bowed limbs, barrel chest, scoliosis, large eyes, underbite, triangular
shaped head or face and some may have blue sclera. Many are able to participate in
non-contact sports such as golf or swimming and most people are able to become
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