von Wil·le·brand disease (v?n w?l??-br?nd?, fôn v?l??-bränt?)n. A usually genetic bleeding disorder caused a deficiency or an abnormality of a clotting factor that affects platelet adhesion.[After Erik Adolf von Willebrand (1870-1949), Finnish physician.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.