There are about 350 disorders in this group. They are generally diagnosed by an x-ray of the skeleton. They affect bone (bone dysplasias) and/or cartilage (chondrodysplasias).
Most result in very short stature, such as in Achondroplasia, but some have average or tall stature. Joints may be either contracted or hypermobile. Some people have congenital heart defects, cleft palate, extra fingers or visual disabilities. About 50 of these disorders result from disturbances in bone mineralization and are managed jointly with the Centre for Children’s Bone Health.