Osteogenesis imperfecta is a group of inherited disorders that mainly affect the bones, causing them to be fragile and easily broken. Type I osteogenesis imperfecta is the mildest and most common type of the disorder. Osteogenesis imperfecta, type I is a subtype of osteogenesis imperfecta. The signs and symptoms of this condition vary, but osteogenesis imperfecta type I tends to be milder than the other types of osteogenesis imperfecta. Bones are brittle and easily broken. Multiple fractures are common during childhood and adolescence, and often result from minor trauma. People with this condition have a blue or gray tint to the part of the eyeball that is usually white (the sclera). Other signs and symptoms include loose joints, skin that bruises easily, and curvature of the spine (scoliosis). Hearing loss occurs in at least half of people with type I osteogenesis imperfecta, usually beginning in the late teens or early adulthood. Decreased hearing is usually caused by problems with the middle ear bones (conductive hearing loss), but in some cases the inner ear and nerves from the ear to the brain also become involved (mixed conductive and sensorineural hearing loss).