The connective tissues of the skeleton consist of cartilage, bone, tendon, muscle and ligaments. These tissues come together to form the skeleton and allow it to keep its shape and strength so that it can do its job of providing protection, moving, and producing blood. When your child has a connective tissue disorder, the proteins or components that make up connective tissues can be abnormal for several different reasons. In some cases, it is because they become inflamed or irritated. In others, it is because there is a change in a gene that affects the protein.