This syndrome is a genetical disorder with symptoms result from deficit in the formation of connective tissue, especially collagen fiber biosynthesis. In these patients, there is hyperelasticity and fragility of the skin and mucosa. Injuries sever bleeding, internal bleeding and hemartrosis may be seen in these patients. Wounds leave scars after healing. There is recurrent dislocation of the joints, especially knee and temporomandibular joints. Dentists should know the symptoms of this syndrome and its complications during dental treatments.