n :  a protein secreted esp. by endothelial cells that circulates in plasma as a large variable aggregation consisting usu. of repeating dimers, that mediates platelet adhesion to collagen in subendothelial tissue at injury sites, that is often found complexed to factor VIII in plasma where it serves to protect it from degradation, and that is deficient or defective in individuals affected with von Willebrand's disease - called also VW factor 
 
Willebrand, Erik Adolf von (1870-1949), Finnish physician. He described von Willebrand's disease first in 1926 and again in 1931 in a follow-up article.
 
 
 
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