Ehlers-Danlos syndrome (EDS) is an inherited connective tissue disorder with varying manifestations that have been classified into six major types: Classical (type I & II), Hypermobility (type III), Vascular or VEDS (type IV), Kyphoscoliosis (type VI), Arthrochalasia (types VII-A & B), and Dermatosparaxis (type VII-C). EDS is caused by a defect in the formation of collagen, specifically mutations in the COL5A and COL3A genes, which can cause hypermobility in joints. EDS gets its name after two physicians who identified it at the turn of the 20th century, Edvard Ehlers (Denmark) and Henri-Alexandre Danlos (France).
The types of EDS are not gradations in severity, but represent distinct disorders that "run true" in a family. The different types are classified according to their manifestations of signs and symptoms. The underlying features of all forms of EDS is a genetic alteration at the molecular level which causes abnormalities and (weakened) defective connective tissue within the collagen itself.
Collagen is a protein that acts like "glue", which holds the body together, and makes the connective tissue strong and provides elasticity. Each type of EDS has a different collagen abnormality, but all share, in varying degrees certain manifestations. This faulty collagen causes structural changes to the skin, ligaments, tendons, bone, fascia and eyes. Some types of EDS are characterized by weaknesses in the walls of the hollow organs of the gastrointestinal tract, in the esophagus, the cardiovascular system, uterus, bladder, blood vessels and the arteries. Diagnosing a specific type of EDS may not be easy, however, because the manifestations often overlap. The fundamental understanding of this complex disorder and its varied manifestations is essential to prevent major life-threatening complications.