The examination of the ITI system in disputed paternities

ITIH1*Q0iwate, a null allele of inter-alpha-trypsin inhibitor H1 caused by deletion/frameshift mutation

The molecular characterization of the first example of null allele in the inter-alpha-trypsin inhibitor H1 (ITIH1) system, ITIH1*Q0iwate, encountered as apparent inverse homozygosity of ITIH1 phenotypes between mother and child in a paternity case, is described. Single-strand conformation polymorphism analysis and subsequent sequencing showed that deletion of a single nucleotide in the codon for Lys87 results in a frameshift causing a terminator codon downstream of the deletion. This leads to premature termination of ITIH1 protein translation at amino acid 128, resulting in a truncated protein.

Simple detection of the inter-alpha-trypsin-inhibitor (ITI) polymorphism by isoelectric focusing with direct immunofixation

The inter-alpha-trypsin inhibitor (ITI) polymorphism was analysed in a German population, using polyacrylamide gel isoelectric focusing with subsequent direct immunofixation with monospecific ITI antisera. Gene frequencies of ITI*1, ITI*2, ITI*3, and ITI*4 were calculated to be 0.6150, 0.3753, 0.0078 and 0.0019, respectively. In our study the allele ITI*4 is described for the first time in a German population.

The polymorphism of the plasma inter-alpha-trypsin inhibitor (ITI) and its relationship to the heavy chain H1 subunit gene (ITIH1) at 3p211-212

We investigated the ITI protein polymorphism in linkage analysis, using DraI and SstI as restriction fragment length polymorphism (RFLP) markers for the ITIH1 gene. Isoelectric focusing (IEF) classification from 76 individual plasma samples and RFLP analysis from the corresponding DNA preparations disclosed linkage disequilibrium between the phenotypic IEF patterns of the two common ITI alleles, ITI*1 and ITI*2, and the diallelic DNA polymorphisms of two ITIH1 RFLPs, represented by DraI 4.0 kb and DraI 2.4 + 1.6 kb, and by SstI 6.7 kb and SstI 6.0 + 0.7 kb, for the ITI 1 and ITI 2 IEF phenotypes, respectively, and by DraI 4.0/2.4 + 1.6 kb and SstI 6.7/6.0 + 0.7 kb for the heterozygous ITI 1-2 IEF phenotype. Linked segregation between either of the RFLPs and the polymorphic ITI plasma protein locus has been established in nine informative family pedigrees. The less frequent allele in Europeans, ITI*3, is not represented by a further allelic restriction fragment in either RFLP. The significant linkage disequilibrium observed in this genetic study indicates that the ITI locus, with the alleles ITI*1 and ITI*2, must be close to, or reside within, the ITIH1 gene. The diallelic ITI protein polymorphism therefore provides an informative phenotypic marker system for chromosome 3p211-212.

Genetic polymorphism of inter-alpha-trypsin inhibitor (ITI) in the Basque Country (northern Spain)

The genetic polymorphism of inter-alpha-trypsin inhibitor (ITI) was analyzed in 2 samples of 554 residents and 303 autochthonous healthy unrelated individuals from the Basque Country (northern Spain), by isoelectric focusing on miniaturized polyacrylamide gels followed by immunoblotting. The allele frequencies were ITI*1 = 0.586, ITI*2 = 0.402 and ITI*3 = 0.012 in residents and ITI*1 = 0.548, ITI*2 = 0.449 and ITI*3 = 0.003 in the autochthonous population. These allele frequencies were compared with those reported in other European populations.