In medicine and rheumatology, connective tissue diseases are "a heterogeneous group of disorders, some hereditary, others acquired, characterized by abnormal structure or function of one or more of the elements of connective tissue, i.e., collagen, elastin, or the mucopolysaccharides."[1]
Cartilage disease
Collagen disease
Connective tissue disease due to autoimmune disease may have detectable autoantibodies to autoantigens such as: