Polymorphism of coagulation factor XIII B subunit: Further occurrence of FXIIIB*15 in Japanese and phenotyping in bloodstains

Abstract

The polymorphism of FXIIIB was investigated in 555 unrelated Japanese individuals using isoelectric focusing and immunoblotting. Five common phenotypes and a rare variant type FXIIIB 15-3 were observed. The allele frequencies were FXIIIB*1 = 0.3063, FXIIIB*2 = 0.0162, FXIIIB*3 = 0.6766 and FXIIIB*15 = 0.0009. Phenotyping was also possible from bloodstains stored at 37 degrees C for up to 4 months and from bloodstains stored at room temperature and at 4 degrees C for over 6 months. The FXIIIB system can provide a new powerful genetic marker for the medicolegal grouping of bloodstains.

Distinct C‐terminus of the B subunit of factor XIII in a population‐associated major phenotype: the first case of complete allele‐specific alternative splicing products in the coagulation and fibrinolytic systems

“…Accordingly, it has been proven that the protein product of FXIII-B*3 exists exclusively in individuals with this genotype. found to be 0.66 (43 homozygotes and 48 heterozygotes) in the Japanese and 0.18 (two homozygotes and 35 heterozygotes) in the Germans, in good accordance with the previous reports [21,22]. There was close agreement between the observed numbers and numbers expected assuming the Hardy-Weinberg equilibrium, as the expected numbers of FXIII-B*3 are 44 homozygotes and 45 heterozygotes for Japanese (v 2 = 0.29, P = 0.87) and three homozygotes and 32 heterozygotes for Germans (v 2 = 0.82, P = 0.66).…”

“…Plasma samples obtained from individuals were subjected to isoelectric focusing for pH = 5–8, and then to western blotting using a specific anti‐human FXIII‐B antibody. As labeled by names and arrows, each phenotype consists of one or more unique bands [16–22]. Theoretical pIs of four isoforms, calculated by the gpmaw software program (Lighthouse Data, Odense, Denmark) are given in parentheses.…”

“…When genotyping by PCR‐RFLP had shown that the samples were neither FXIII‐B*2 nor FXIII‐B*4, and the results of PCR‐APLP showed that they were not FXIII‐B*3, the genomic samples were classified as FXIII‐B*1, because these four FXIII‐B alleles (FXIII‐B*1– FXIII‐B*4) were reported to predominate in 1604 unrelated healthy German individuals (100%) [21], and in 554 of 555 Japanese individuals (99.8%) [22].…”

“…The heterogeneity of FXIII-B was identified first by the Lorand group by isoelectric focusing based on the differential isoelectric point (pI) of each variant protein [15]; FXIII-B was later classified into three population-associated major phenotypes, FXIII-B*1, FXIII-B*2, and FXIII-B*3 (* indicates an allele), for European, African and Asian populations, respectively [16][17][18][19]. In addition, there are many rare alleles [17,18,[20][21][22], such as FXIII-B*4 in Caucasians [20,21], as well as a large number of haplotypes of the F13B gene, as listed in databases, including HapMap Data. The association of some genotypes of FXIII-B with thrombosis has been proposed [23][24][25][26].…”

Allele‐specific alternative splicing; the tail of FXIII‐B tells its own tale

“…Such clear segregation of the three alleles over three continents is a rather unique genetic feature of FXIII‐B. Several other minor alleles have also been described, including B*4, B*6, B*13, B*14 and B*15, but especially the latter alleles are relatively rare [17–19]. The genetic variation of FXIII‐B is responsible for some of the population variability in FXIII activity, with the highest activity observed for FXIII‐B*2, followed by FXIII‐B*1 and the lowest activity for FXIII‐B*3 [20].…”