Skeletal dysplasia is a term used to describe genetic conditions that affect the growth of a child’s cartilage, bones, and connective tissue. There are more than 400 dysplasias, many of which cause changes in the shape and size of the skeleton. These changes are most noticeable when they occur in the arms, legs, head, or spine. Some dysplasia, such as achondroplasia, result in short stature.