Molecular Basis for Polymorphism of the “a” Subunit of Coagulation Factor XIII

Two major alleles of the “a” subunit of coagulation factor XIII (F13A), F13A*1 and * 2 (Board 1979) were found to split into four alleles, F13A*1A, *1B, *2A,and *2B (fig.1, Suzuki et al. 1988). We hypothesized on the basis of the differences in isoelectric points between the four allele products that two point mutations and one intragenic crossing over event might generate the four alleles (fig 2). In this study the 14 coding exons (Ichinose and Davie 1988) of the four F13A alleles were amplified by using polymerase chain reaction (PCR) and sequenced to reveal nucleotide differences between the alleles and to provide support for the hypothetic model, and nucleotide changes in two rare variant alleles were also presented.