Short humerus (upper arm bone) and short femur (upper leg bone).Resembles Type II and Type III OI in appearance and symptoms.Diagnosed by bone biopsy or genetic studies.“Fish-scale” appearance to bone when viewed under the microscope.Not always diagnosed at birth, and symptoms progress over time.Resembles Type IV OI in appearance and symptoms.“Mesh-like” appearance to bone when viewed under the microscope.Calcification of the membrane between the radius and ulna (the bones of the forearm), which results in restricted arm movement.(A callus is an area of new bone that is laid down at the fracture site as part of the healing process.) Unusually large calluses, called hypertrophic calluses, at the sites of fractures or surgical procedures.A dense band seen on x-rays by the cartilage growth plate of the long bones.Clinically similar to Type IV OI in appearance and symptoms.Possible changes to strength and color of teeth.Bones break easily, sometimes before birth, with most broken bones occurring before puberty.Possible malocclusion of the teeth, meaning they are not aligned properly.Possible changes to the strength and color of teeth with tooth fracture.Possible lung problems that worsen with age.Curved spine and compression or collapse of vertebrae.Poor muscle development in arms and legs.(Broken bones are often present at birth, and x-rays may reveal healed bone breaks that occurred before birth.)

Easily broken bones with very little trauma over a lifetime.

Most severe type among those who survive the neonatal period and usually results in the greatest number of physical disabilities.

Numerous broken bones that develop before birth while the baby is still in the womb.

Causes death at birth or shortly after, because of the inability to breathe.

Normal collagen structure, but less than the normal amount is produced.

Possible changes to the strength and color of teeth.

Curved spine with potential for compression of the vertebrae (spine bones) with aging.

Blue, purple, or gray tint to sclera (whites of the eyes).

No change or only slight changes to stature with aging.

Bones likely to break from mild to moderate trauma, with most broken bones occurring before puberty.

The remaining types are rare and still being studied. Following is an overview of the types most often diagnosed.

Other types of OI have symptoms that fall between Type I and Type II. Type I is the mildest and most common form of OI. There are several types of OI, and different classifications are used based on the severity of the disease or on the nature of the underlying gene defect.

Jodi picoult brittle bone disease