Klippel-Trénaunay syndrome /klipel′ trānōnā′/ [Maurice Klippel, French neurologist, 1858–1942; Paul Trénaunay, 20th-century French physician] , a rare condition affecting the development of blood vessels, bones, and soft tissues. Large cutaneous hemangiomas, persistent nevus flammeus, and skin varices are associated with this syndrome. Also called Klippel–Trénaunay–Weber syndrome.