Osteogenesis imperfecta (OI), also known as brittle bone disease, is an inherited genetic disorder that affects connective tissue and causes bones to break easily, normally without any recognizable cause. Its name, “osteogenesis imperfecta”, literally means imperfect bone formation. So far, eight forms of the disease have been identified, classified from Type I to Type VIII. Each module describes the severity of the diseased person. For example, Type I is the mildest form of the disease, while Types II, III, VII and VIII are the most severe. People with osteogenesis imperfecta have muscle weakness, loose joints, weak tissue, fragile skin, and bones that can easily become deformed. be fractured. Mild OI can cause a person with the disease to suffer only a few fractures, while someone with one of the severe or lethal forms of OI can suffer hundreds of fractures over their lifetime, leading to bone deformities. Sometimes fractures can even occur before birth. Adults and children diagnosed with the disease are often short in stature, have triangular-shaped faces, and may have discoloration of the sclera of the eye. The sclera is a white tissue, but a person with OI may have a blue or gray sclera. Other symptoms include a curved spine, brittle teeth, frequent nosebleeds, difficulty breathing, and hearing loss that can begin in childhood or early adulthood. About 90% of all OI cases have an autosomal dominant mode of inheritance, meaning someone only needs to inherit one copy of the abnormal gene from a parent in order to get the disease. These dominant forms of osteogenesis imperfecta are caused by a mutation in the COL1A1 or COL1A2 genes. These genes encompass the...... half of the paper ......if.org/site/PageServer?pagename=RS_RecessiveOIFast facts. (n.d.). Osteogenesis Imperfecta Foundation. Retrieved March 20, 2014, from http://www.oif.org/site/PageServer?pagename=fastfactsOsteogenesis imperfecta. (n.d.). WebMD. Retrieved March 20, 2014, from http://www.webmd.com/children/osteogenesis-imperfecta-11141Osteogenesis imperfecta. (n.d.). Johns Hopkins Medicine. Retrieved March 21, 2014, from http://www.hopkinsmedicine.org/healthlibrary/conditions/adult/bone_disorders/osteogenesis_imperfecta_85,P00123/Osteogenesis imperfecta. (2014, March 17). Genetics Home Reference. Retrieved March 20, 2014, from http://ghr.nlm.nih.gov/condition/osteogenesis-imperfectaOsteogenesis imperfecta: MedlinePlus medical encyclopedia. (2014, February 26). United States National Library of Medicine. Retrieved March 22, 2014, from http://www.nlm.nih.gov/medlineplus/ency/article/001573.htm