Connective tissue disease/Definition
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, and thus within the specialty of rheumatology; many involve autoimmunity
This definition is at least in part based on: Anonymous (2020), Connective tissue disease (English). Medical Subject Headings. U.S. National Library of Medicine.