People with osteogenesis imperfecta (OI) have bones that fracture easily, low muscle mass, and joint and ligament laxity. There are six major types of OI, ranging in severity from mild to lethal.

The appearance of people with OI varies considerably. Individuals may have a blue or gray tint to the sclera (whites of the eyes), thin skin, growth deficiencies, and fragile teeth. They may develop scoliosis, respiratory problems, and hearing loss.

Also known as “brittle bone disease,” this disorder arises from mutations in the two genes that make type I collagen, a protein important to bones and skin. These mutations cause the body to make either too little or poor-quality type I collagen.

The OI Foundation has published fact sheets on many topics related to understanding and living with OI.