Identification of the mutation site in factor XII Tenri. (A) Pedigree of the factor XII Tenri family. Affected subjects with reduced factor XII levels are shadowed and the proband is indicated by an arrow. Deceased family members and unexplored subjects are indicated by ○/ or □/ and n.t., respectively. Antigen/activity levels of factor XII are shown. (B) LIS-SSCP analysis of exon 3 of factor XII gene. PCR fragments of exon 3 derived from a normal subject (left) and the proband (right) were analyzed by LIS-SSCP as described in Materials and Methods. (C) Nucleotide sequence showing the A to G substitution in exon 3 of the factor XII Tenri gene. This substitution mutates Tyr34 to Cys in the type II domain of factor XII. (D) PCR-Kpn I digestion analysis of the factor XII Tenri family. For each member, exon 3 amplified by PCR as described in Materials and Methods was digested with KpnI and subsequently analyzed by agarose gel electrophoresis. PCR product from normal allele showed a cleaved fragment of 141 bp, whereas that from Tenri-type allele showed an uncleaved band of 163 bp.