In 1933 they co-authored an account of the disease, renaming it "constitutional thrombopathy". Numerous papers were subsequently published on the disease and it became eponymously known as von Willebrand disease between the late 1930s and the early 1940s. In 1957, it was discovered that von Willebrand disease is caused by a deficiency of a protein in blood plasma that enables hemostasis. The protein was characterised in 1971, and is known as von Willebrand factor. Von Willebrand factor has two functions. Firstly, it is the carrier molecule for factor VIII, the anti-hemophilic factor. Secondly, it promotes the aggregation of platelets and attachment to the vessel wall. In 2011, Jan van Gijn and Joost P. Gijselhart, writing in the Nederlands Tijdschrift voor Geneeskunde, remarked that Von Willebrand was not far wrong when he named the disease "hereditary pseudohemophilia". Personal life and death In his personal life, Von Willebrand was described as a mild-mannered and modest man. He married Walborg Maria Antell in 1900, and had two daughters. As a member of the Swedish-speaking minority in Finland, he was a supporter of Ossian Schauman's Folkhälsan, which promoted social welfare and health care for Swedish-speaking Finns. His research on the bleeding condition of the Åland islanders was of particular interest to him, as it was a hereditary disorder that affected the Swedish-speaking minority. After his retirement in 1933 he became an avid gardener and a supporter of nature conservation. Von Willebrand died on 12 September 1949, at the age of 79. In 1994, he was commemorated with a stamp issued by Åland. The stamp was one in a set of two: the other commemorated Erik Jorpes, known for his pioneering work on heparin. Publications The following list of publications is compiled from Lassila, R.; Lindberg, O. (2013). "Erik von Willebrand". Haemophilia. 19 (5): 645. References Sources 1870 births 1949 deaths Academic staff of the University of Helsinki Finnish hematologists Finnish people of German descent People from Vaasa Swedish-speaking Finns University of Helsinki alumni 20th-century Finnish physicians