Genetic studies of low-abundance human plasma proteins. X. Coagulation factor XIIIB variants in blacks.

Human coagulation factor XIIIV (F XIIIB) demonstrates genetically determined-structural variation with three common and several rare alleles. Population genetics studies reveal enormous intra and interracial group variation. In the present study, using isoelectric focusing and immunoblotting, we have determined for the first time the polymorphic occurrence of F XIIIB allelic forms in a native African population, namely Nigerian Blacks. In addition, F XIIIB data have been extended to various US Black populations. The characteristic feature of the black gene pool is the relative high frequency of the F XIIIB2 allele, the highest being in Nigerians (0.723). The F XIIIB6 allele is present at a polymorphic level in both the US and Nigerian Blacks and appears to be a unique black allele marker. The present technique has demonstrated several new alleles designated: F XIIIB18, FXIIIB22, F XIIIB23 and F XIIIB24. Among these new alleles the F XIIIB*23 exists at polymorphic level in both the US and Nigerian Blacks and is another unique Black allele marker of potential significance in population genetics studies.