The following 4 types of Osteogenesis Imperfecta have been reported ...

• Type I - Mild forms

• Type II - Extremely severe

• Type III - Severe

• Type IV - Undefined

Type I is the most common and mildest form of Osteogenesis Imperfecta. While the structure of the collagen is normal, there is less collagen than there should be. There is little or no bone deformity, although the bones are fragile and easily broken. People with Type I Osteogenesis Imperfecta average nearly 40 fractures before puberty; however, they experience only a few fractures after puberty.

The effects of Osteogenesis Imperfecta may extend to the teeth, making them prone to cavities and cracking. The whites of the eyes may have a blue, purple, or gray tint.

Type I individuals have normal or slightly shorter stature with little or no bone deformity. There is less collagen than normal in individuals with type I and they have loose joints and low muscle tone. Many often have Blue Sclera, a condition in which the white of the eye has a blue, purple, or grayish tint. They have a triangular shaped face. Those who have type l also have the possibility of hearing loss.

Some features of Type I Osteogenesis Imperfecta include ..

• Bones fracture easily. There is a 7x greater incidence of overall fracture rate than normal.

• Over a lifetime, numbers of fractures can range from 1-60. Any type of fracture can occur and these become less frequent with age, most commonly affected are the lower limbs.

• Patients have no long-bone deformity.

• Normal or near-normal stature.

• Height is usually normal in individuals with mild forms of OI.

• Triangular-shaped face.

• Scleras (whites of the eyes) usually have a blue, purple, or gray tint.

• Loose joints and muscle weakness.

• Hearing loss beginning in their 20s.

• Scoliosis (curvature of the spine).

• Thin, smooth skin.

• Loose joints.

• Low muscle tone.

• Brittle teeth. When teeth are affected, some may be more affected than others. There is discolouration with enamel fracturing easily from the dentine, causing rapid erosion in both sets.