Genetic polymorphism of the B subunit of human coagulation factor XIII: another classification

Natural selection and the molecular basis of electrophoretic variation at the coagulation F13B locus

Electrophoretic analysis of protein variation at the coagulation F13B locus has previously revealed three alleles, with alleles 1, 2, and 3 each being at high frequency in European, African, and Asian populations, respectively. To determine if this unusual pattern of interpopulation differentiation reflects local natural selection or neutral genetic drift, we re-sequenced 4.6 kb of the gene, encompassing all exons, splice junctions, and 1.4 kb of the promoter, in African, European, and Asian samples. These analyses revealed three major lineages, which correspond to the common protein alleles and differ from each other at a non-synonymous substitution in exon 3 and a novel splice acceptor in intron K. There is previous evidence that these lineages are not functionally equivalent; we therefore carried out case-control analyses and confirmed that variability at F13B modulates susceptibility and/or survivorship in coronary artery disease (P<0.05) and type II diabetes within the coronary artery disease cohort (P<0.01). Tajima's D and Fu and Li's tests did not indicate significant departures from neutral expectations. However, publicly available data from SeattleSNPs and HapMap do indicate highly unusual levels of population differentiation (P=0.003) and an excess of allele-specific, extended haplotype homozygosity within the African population (P=0.0125). Possible causes of this putative signal of selection include hematophagous organisms, infection by pathogens that cause disseminated intravascular coagulation, and metabolic or dietary factors.

The Cayapa Indians of Ecuador: a population study of seven protein genetic polymorphisms

The Cayapa Indians are a population of 3600 individuals living in Ecuador, along the Cayapas River and its tributaries. They are thought to have migrated from the Andes, north of Quito, and settled in the Cayapas area five centuries ago as a consequence of Inca expansion and of the Spanish conquest. In order to study the genetic structure of the Cayapa and their relationships with other native American peoples, and to enquire on the possibility of admixture from nearby Black communities, we have investigated a sample of 139 individuals for seven plasma genetic markers (F13A, F13B, ORM1, AHSG, C6, C7 and APOC2) by isoelectric focusing and immunoblotting. The following gene frequencies have been found: F13A*1 = 0.824, F13A*2 = 0.176; F13B*1 = 0.126, F13B*3 = 0.874; ORM1*1 = 0.554, ORM1*2 = 0.446; AHSG*1 = 0.275, AHSG*2 = 0.725; C6*A = 0.131, C6*B = 0.814, C6*A21 = 0.055; C7*1 = 1.000; APOC2*1 = 1.000. The findings confirm, whenever the comparison was possible, quite a good resemblance of the Cayapa with other Native American populations.

Population genetics of coagulation factor XIIIB in three ethnic groups of Singapore

The distribution of plasma coagulation factor XXIIB polymorphism was determined by PAG isoelectric focusing and immunoblotting in a group of 670 subjects comprising 375 Chinese, 110 Malays and 185 Indians. The frequencies of FXIIIB*1, FXIIIB*2, and FXIIIB*3 were found to be 0.27, 0.03 and 0.70 in the Chinese; 0.33, 0.05 and 0.64 in the Malays and 0.58, 0.08 and 0.33 in the Indians. The phenotypic distribution of FXIIIB alleles was at Hardy-Weinberg equilibrium in all three populations. A two-dimensional principal-components analysis on the basis of three common alleles at the FXIIIB locus among 19 populations, so far studied, clearly differentiates the Negroid, Mongoloid and Caucasoid populations into three major groups with the exception of Amerindians (Minnesota) and US Blacks showing some Caucasoid influence.

Isoelectric focusing in immobilized pH gradients: applications in clinical chemistry and forensic analysis

The applications of isoelectric focusing in immobilized pH gradients in clinical chemistry and forensic analysis are reviewed. Strong emphasis is given to the separation of serum proteins, in particular alpha 1-acidic glycoprotein, acid phosphatase, alkaline phosphatase, alpha 1-antitrypsin, apolipoproteins, complement component, factor B, factor XIIIB, group-specific component, lecithin:cholesterol acyltransferase, phosphoglucomutase, prealbumin, protein C and transferrin. The analysis of human parotid salivary proteins is discussed and an assessment is given of the state of the art in thalassaemia screening.

Analysis of the genetic polymorphism of coagulation factor XIIIB (FXIIIB) by isoelectric focusing

The genetic variants of the coagulation factor XIIIB (FXIIIB) were analyzed by isoelectric focusing, carried out in agarose gels and followed by immunofixation. The FXIIIB phenotypes were visualized by a combined staining procedure with Coomassie Brilliant Blue R-250 and silver nitrate. Improved resolution was accomplished in polyacrylamide gels by hybrid isoelectric focusing in immobilized pH gradients supplemented with carrier ampholytes. We examined a total of 1,604 unrelated, healthy individuals from Southern Germany. The frequencies for the FXIIIB alleles were B*1 = 0.7581, B*2 = 0.0843, B*3 = 0.1568 and B*4 = 0.0019. The theoretical exclusion rate for disputed paternity is 22.35%.

Genetic polymorphism of coagulation factor XIII B subunit in the Japanese population: description of three new rare alleles

Polyacrylamide gel isoelectric focusing (PAGIEF) of neuraminidase-treated EDTA plasma samples followed by electroblotting with enzyme immunoassay was performed to further investigate coagulation factor XIII B subunit (FXIII B) polymorphism. In 435 Japanese subjects PAGIEF patterns of FXIII B were classified into five common and three rare allotypes. This suggested that the FXIII B*2 allele existed in the Japanese population in the same manner as in Caucasians. Three new rare allotypes were considered to be controlled by three rare alleles which were designated FXIII B*13, FXIII B*14, and FXIII B*15, respectively. The gene frequencies calculated from 435 Japanese subjects were FXIII B*1 = 0.2977, FXIII B*2 = 0.0184, FXIII B*3 = 0.6805, FXIII B*13 = 0.0011, FXIII B*14 = 0.0011, and FXIII B*15 = 0.0011, respectively.

Genetic heterogeneity of the B subunit of coagulation factor XIII: resolution of type 2

An apparent discrepancy in phenotyping the genetic polymorphism at the FXIIIB locus by electrophoresis or isoelectric focusing has been investigated. The data indicate that the product of the type 2 allele, which can be detected by agarose electrophoresis, is not resolved from the product of the type 1 allele by isoelectric focusing. The understanding of this problem has previously been confused by the absence or very low frequency of the type 2 allele in Japanese populations studied by isoelectric focusing and electrophoresis. An alternative enzyme-linked immunoblotting technique is described which substantially improves the method for phenotyping products of the FXIIIB locus after electrophoresis.

Coagulation factor XIII: a useful polymorphic genetic marker

The plasmas of two groups of subjects were examined for blood coagulation Factor XIII-A (FXIII-A, F13A) by electrophoresis in agarose using a Tris-EDTA-borate buffer to separate the common variants, F13A*1, F13A*2, and F13A*3. Dimeric subunits were visualized in UV light as monodansyl cadaverine bound to casein at the position of the transglutaminase activity representing F13A. One test group consisted of 307 members of three large Caucasian families. The other consisted of 148 consecutive patients whose plasmas had been sent to the clinical laboratory for determination of prothrombin time. Segregation analysis and father-to-son transmission confirmed that F13A is inherited as an autosomal co-dominant trait. The allelic frequencies in the random sample were F13A*1 = 0.82 and F13A*2 = 0.18. This sample included both blacks and whites, and the gene frequencies were not significantly different in the two races. The gene frequencies among the unrelated spouses of the three white families were A*1 = 0.75, A*2 = 0.24, A*3 = 0.01. Genetic equilibrium was present in both groups. The degree of polymorphism, the availability of blood, the ease of assessment, the absence of selective pressure, and the uniformity of gene frequencies in two major American ethnic groups make F13A a very useful marker for linkage studies and paternity testing. F13A has been provisionally assigned to chromosome 6. Linkage analysis of our family data did not provide evidence of linkage to two chromosome 6 markers, properdin factor B (BF) and glyoxalase 1 (GLO). The highest lod score (Z) was between F13A and the Kidd (Jk) blood group (theta = 0.68 at = 0.24).

Improved coagulation factor XIII B (FXIIIB) phenotyping after neuraminidase treatment of plasma and first description of the FXIIIB 2 phenotype

The genetically determined polymorphism of the B subunit of the human coagulation factor XIII (FXIIIB) was investigated by an improved technique of immunofixation agarose gel electrophoresis (IAGE). Employing neuraminidase (CPN) treatment of fivefold-concentrated fresh plasma and monospecific anti-human FXIIIB antiserum an excellent resolution of phenotypes was possible. Six phenotypes, FXIIIB 1,2-1,2,3-1, 3-2 and 3 were detected among 178 unrelated blood donors from Hessen, Germany, the FXIIIB 2 homozygote for the first time. Our findings confirm the 'reduced' two-allele-model of Kera et al. [10]. For the first time the allele frequencies were determined in a European population: FXIIIB*1 = 0.708, FXIIIB*2 = 0.109, FXIIIB3* = 0.183. As in family studies no unexpected phenotypes were observed in the offspring, FXIIIB might become a useful genetic marker in paternity testing, the single exclusion chance for non-fathers being 23.7%.

Genetic polymorphism of coagulation factor XIIIB subunit in Japanese

Genetic polymorphism of coagulation factor XIIIB subunit in Japanese has been described, using a thin-layer agarose gel isoelectric focusing followed by immunofixation. Phenotypes of factor XIIIB subunit were essentially classified into three common patterns A, B and AB. It is estimated that the phenotypes are determined by two codominant alleles. A new rare variant B' has been detected in Japanese. Gene frequencies calculated from 304 individuals showed FXIII-BA = 0.735, FXIII-BB = 0.252 and FXIII-BB' = 0.013, respectively. The distribution of phenotypes fitted the Hardy-Weinberg equilibrium.