family a has four members in three consecutive generations that have both von willebrand 's disease and telangiectasias . von willebrand 's disease in this family is characterized by decreased ristocetin cofactor ( fviii-vwf ) , variably depressed factor viii coagulant ( fviii-ahg ) , and factor viii-related antigen ( fviii-agn ) levels .
C0042974
von willebrand 's
C0015506
ahg