Characteristics of the Montreal platelet syndrome kindred. (A) Genogram and laboratory data with affected family members indicated by shading and previously studied subjects by bold text and bold genogram symbol outline. In the hemostatic variables, HMW indicates high molecular weight; N/D, not determined; □, subject lost to follow-up; therefore, permission was not obtained to print identifying information. *Normal range, 7 to 11 fL; †Normal, < 9.5 minutes; ‡normal range, 84 to 176 seconds; §normal range, 63 to 111 seconds. (B) Sodium dodecyl sulfate–agarose gel electrophoresis of plasma VWF multimers showing loss of HMW VWF multimers in representative subjects affected with MPS (L.T.B., I.B.) and normal plasma HMW VWF multimers in a representative unaffected family member (B.B.) and a control (C). (C) Peripheral blood film showing large platelets and platelet clumping.