Plasma and platelet VWF multimers in unaffected and affected family members. Plasma and platelet VWF multimers were assessed by SDS-agarose gel electrophoresis and Western blotting. Vertical line(s) have been inserted to indicate a repositioned gel lane. Lane 1 in both frames: platelet and plasma VWF of unaffected heterozygous family member, II-1. Lanes 2-4: affected family members II-2, II-3, and II-4 with a homozygous N528S VWF mutation. Affected family members have an abnormal plasma multimer distribution with a relative decrease of large multimers and pronounced oligomers and either a complete loss (II-2, II-3) or a severely decreased concentration (II-4) of large platelet VWF multimers.