Osteogenesis imperfecta (OI) is a genetic disorder that is commonly called “brittle bone disease.” Fernando, a student with Type III OI, prefers his walker slightly shorter than his therapist does.
Over the last several issues of SCHOOL BUS FLEET, we’ve looked at a variety of medical conditions and how they affect emergency evacuations from the school bus.
In the fifth edition of the series, we will discuss evacuating students who have osteogenesis imperfecta (OI).
Specifics of OI
OI is a genetic disorder that is commonly called “brittle bone disease.” The disorder is inherited, and both genders are affected. OI is characterized by bones that break easily, often from little to no apparent cause.
It has been found that children who have OI have a problem with the development of collagen in their body. Collagen can be described as the framework upon which bone and tissues are built. If the collagen is defective, bones fracture more easily and muscles lack tone.
There are currently four known types of OI.
Type I OI:
• This is the mildest and most common form.
• These children have half the normal amount of collagen. However, this collagen is structurally normal.
• They may have muscle weakness, joint laxity and flat feet along with dislocations and sprains.
• Life expectancy seems average.
Type II OI:
• This is the most severe form.
• Infants are quite small at birth, and they are born with multiple fractures, an unusually soft skull and an unstable neck.
• Almost all infants with Type II die at or shortly after birth.
Type III OI:
• These children are born with fractures, and X-rays may reveal healed fractures that occurred before birth.
• They may have anywhere from several dozen to several hundred fractures in a lifetime. With these children, surgical correction of long bone bowing and scoliosis is common.
• They may need supplemental oxygen.
• Life expectancy varies.
Type IV OI:
• This is considered the moderate form.
• These children will have frequent fractures that decrease after puberty.
• They have mild to moderate bone malformation.
• Life expectancy appears to be average.
With all four types of OI, fractures decrease after puberty.
Researchers are beginning to identify additional types of OI, namely Type V and Type VI.