Genetic polymorphism of the B subunit of coagulation factor XIII in Libyans: occurrence of a fourth common allele, FXIIIB*6.

FXIIIB phenotypes were determined in neuraminidase-pretreated serum samples by using isoelectric focusing in ultrathin-layer polyacrylamide gels containing 1 M urea and subsequent immunoblotting. In a Libyan population sample from Tripoli, (n = 108) nine different phenotypes as products of four common alleles were recognized, with frequencies as follows: FXIIIB*1 = 0.6574, FXIIIB*2 = 0.2454, FXIIIB*3 = 0.0741 and FXIIIB*6 = 0.0231. It is suggested that FXIIIB*6 is the fourth common allele of the FXIIIB system in this population.