The ITI system in South Koreans and Iranians analysed by an improved classification procedure. Distribution of alleles and description of "new" phenotypes.

Phenotype and gene frequency distributions of the inter-alpha-trypsin inhibitor (ITI) system were analysed in populations from southern Korea and from Iran. The gene frequencies of the common alleles ITI*I and ITI*2 were 0.532 and 0.422, respectively, in southern Korea, and 0.612 and 0.354, respectively, in Iran. The postulated third allele, ITI*3, was found in the homozygous form. Gene frequencies of this rare allele were calculated to be 0.042 and 0.029 in Korea and Iran, respectively. Two additional rare alleles, ITI*4 and ITI*5, determine further phenotypes found in the population from Taejon (Korea) and Iran, respectively, in combination with the common ITI*2 allele. Gene frequencies of ITI*4 and ITI*5 were calculated to be 0.006 and 0.005, respectively. For phenotype classification, untreated sera were separated by isoelectric focusing (IEF) on polyacrylamide gels followed by immunoblotting.