• OI Type I
• OI Type II
• OI Type III
• OI Type IV

The most severe type of OI is type II. This form of the disease affects as many as one in sixty thousand people. Type II is usually caused by a new gene mutation. Many affected newborns do not live past birth, mainly due to respiratory problems, and those that do have very difficult lives. Infants who survive are severely affected. In recent years some patients with OI Type II have survived into young adulthood.

Affecting approximately 10 percent of people with OI, Type II is the most severe form of this disease. The result of a spontaneous gene mutation, the collagen in Type II OI is improperly formed. The bones of people with Type II OI are extremely fragile and often have severe deformities. Type II OI frequently causes death at or shortly after birth.

Type II can be further subclassified into groups A, B, C, which are distinguished by radiographic evaluation of the long bones and ribs. Type IIA demonstrates broad and short long bones with broad and beaded ribs. Type IIB demonstrates broad and short long bones with thin ribs that have little or no beading. Type IIC demonstrates thin and longer long bones with thin and beaded ribs.

These individuals have major bone deformity caused by numerous bone fractures. The collagen in their bones is improperly formed. They have a very small stature and extremely underdeveloped lungs.

Some features of Type II Osteogenesis Imperfectainclude:

• Most severe form.
• Frequently lethal at or shortly after birth, often due to respiratory problems.
• Numerous fractures and severe bone deformity.
• Small stature with underdeveloped lungs.
• Tinted sclera.
• Collagen improperly formed.