Mutation in the C-terminal part. G570R (11482 G → C) found in case C-82 giving rise to a CRM-positive phenotype (FXII:C 10%, FXII:Ag 74%). (A) Wild-type protein structure of the light chain. (B) No disulfide bond formed in FXII Washington D.C. (C) Hypothetical model for FXII G570R. No disulfide bond in putative protein structure of FXII G570R. (D) Wild-type DNA sequence. (E) Heterozygous C-82. Wild-type and mutated sequences are superimposed. (F ) Reverse sequence of C-82. The arrow indicates the mutation.