Osteogenesis imperfecta (OI) is a genetic disorder in which bones break easily. Sometimes the bones break for no known reason. OI can also cause weak muscles, brittle teeth, a curved spine, and hearing loss. OI is caused by one of several genes that aren't working properly. When these genes don't work, it affects how you make collagen, a protein that helps make bones strong.
Legg-Calvé-Perthes disease is a bone disorder that affects the hips. Usually, only one hip is involved, but in about 10 percent of cases, both hips are affected. Legg-Calvé-Perthes disease begins in childhood, typically between ages 4 and 8, and affects boys more frequently than girls.
Scoliosis causes a sideways curve of your backbone, or spine. These curves are often S- or C-shaped. Scoliosis is most common in late childhood and the early teens, when children grow fast. Girls are more likely to have it than boys. It can run in families. Symptoms include leaning to one side and having uneven shoulders and hips.
Metatarsus adductus is a foot deformity. The bones in the front half of the foot bend or turn in toward the body. etatarsus adductus is thought to be caused by the infant's position inside the womb. Newborns with metatarsus adductus may also have a problem called developmental dysplasia of the hip (DDH), in which the thigh bone slips out of the hip socket.