“Osteogenesis imperfecta (OI) is a genetic or heritable disease in which bones fracture (break) easily, often with no obvious cause or minimal injury. OI is also known as brittle bone disease, and the symptoms can range from mild with only a few fractures to severe with many medical complications.

For most people, a change or defect in the genes that carry the instructions for making type I collagen causes OI.  Type I collagen is a material in bones that helps make them strong. The defect in the genes causes the body to make collagen incorrectly or not make enough, leading to weak bones that break more easily. There is no way to prevent the disease.”

National Institute of Arthritis and Musculoskeletal and Skin Disorders (Osteogenesis Imperfecta Symptoms, Types, & Causes | NIAMS)