PCR strategy for analysis of the FXII gene. Exon-intron organization, the localization of primers, and the positions of the sequence alterations are depicted. The brackets indicate the association between the different Taq I-alleles and their associated mutations in the 5′ upstream region and exon 12, respectively. The mutations R353P,4 10586(DelG),17 and C571S³ depicted in the lower part were not detected in our group of patients.