Heritable (genetic) disorders of connective tissue are a family of more than 200 disorders that affect connective tissues. These disorders result from alterations (mutations) in genes, and thus are called “heritable.” All of these diseases are directly related to mutations in genes that are responsible for building tissues. Alterations in these genes may change the structure and development of skin, bones, joints, the heart, blood vessels, lungs, eyes, and ears. Some mutations also change how these tissues work.