Distribution of alpha-1-antitrypsin phenotypes in Sweden

The distribution of phenotypes of alpha-1-antitrypsin (Pi) in 1,062 unrelated Swedes was determined by isoelectric focusing with carrier ampholytes. The frequencies calculated were: PiM1 = 0.6940, PiM2 = 0.1384, PiM3 = 0.1139, PiZ = 0.0231, PiS = 0.0245, PiF = 0.0038, Pivar = 0.0024. A mother-child material consisting of 194 pairs is also presented.     

Distribution of alpha-1-antitrypsin (Pi) phenotypes in Denmark determined by separator isoelectric focusing in agarose gel

The distribution of phenotypes of alpha 1-antitrypsin (Pi) in 909 unrelated Danes was determined by the use of separator isoelectric focusing in agarose gel. The frequencies calculated were: PiM1 = 0.728, PiM2 = 0.136, PiM3 = 0.082, PiZ = 0.023, PiS = 0.022, PiF = 0.006, Pivar = 0.003. The segregation of phenotypes in 39 families with 94 children is presented. The advantages and disadvantages of the method are discussed.     

Inheritance of PiM subtypes. A study of 151 families with a total of 242 children and of 142 mother-child pairs.

Pi phenotypes were classified by isoelectric focusing in sera of 151 families with a total of 242 children and in sera of 142 mother-child pairs. The six common subtypes of PiM are genetically determined by three alleles named PiM1, PiM2, and PiM3. No exceptions to the postulated mode of inheritance have been found. The possibility of further heterogeneity of the intermediate variant PiM3 is discussed.     

Polymorphism of alpha-1-antitrypsin in hematological malignancies

Alpha-1-antitrypsin (AAT) or serine protease inhibitor A1 (SERPINA1) is an important serine protease inhibitor in humans. The main physiological role of AAT is to inhibit neutrophil elastase (NE) released from triggered neutrophils, with an additional lesser role in the defense against damage inflicted by other serine proteases, such as cathepsin G and proteinase 3. Although there is a reported association between AAT polymorphism and different types of cancer, this association with hematological malignancies (HM) is, as yet, unknown. We identified AAT phenotypes by isoelectric focusing (in the pH 4.2-4.9 range) in 151 serum samples from patients with HM (Hodgkins lymphomas, non-Hodgkins lymphomas and malignant monoclonal gammopathies). Healthy blood-donors constituted the control group (n = 272). The evaluated population of patients as well as the control group, were at Hardy-Weinberg equilibrium for the AAT gene (χ(2) = 4.42, d.f.11, p = 0.96 and χ(2) = 4.71, d.f.11, p = 0.97, respectively). There was no difference in the frequency of deficient AAT alleles (Pi Z and Pi S) between patients and control. However, we found a significantly higher frequency of PiM1M1 homozygote and PiM1 allele in HM patients than in control (for phenotype: f = 0.5166 and 0.4118 respectively, p = 0.037; for allele: f = 0.7020 and 0.6360 respectively, p = 0.05). In addition, PiM homozygotes in HM-patients were more numerous than in controls (59% and 48%, respectively, p = 0.044). PiM1 alleles and PiM1 homozygotes are both associated with hematological malignancies, although this is considered a functionally normal AAT variant.     

Genetic polymorphism and rare variants of alpha 1-antitrypsin in the population of Moscow. Research using isoelectric focusing on an ultrathin gel

The data are presented on distribution of subtypes and rare variants of Pi system for Moscow population. Serum samples were obtained from 210 families of healthy newborn (father-mother-newborn) from several Moscow maternity hospitals. Phenotypes of alpha 1-antitrypsin were detected by isoelectric focusing in ultrathin layer polyacrylamide gel with the range 3.5-6. In this study 5 common PiM subtypes (except M3M3) were found. The observed distribution of Pi subtypes shows a good agreement with the Hardi-Weinberg equation. The gene frequencies of the subtypes estimated for Moscow population were as follows: PiM1-0.7662, PiM2-0.1779, PiM3-0.0398. They did not show any difference from the corresponding frequencies in other European populations. In the course of our studies, some rare phenotypes, such as MS, MZ, FM and IM that were observed in most European populations, were detected. Furthermore, a very rare variant (MT) which had been only once revealed in European population, was found. The total gene frequency of all rare variants was 0.0162.     

Alpha1-antitrypsin: further genetic heterogeneity revealed by isoelectric focusing.

Alpha1-antitrypsin is a major human serum protein that shows an extensive polymorphism. Genetic heterogeneity has previously been demonstrated by starch gel electrophoresis. By applying analytical isoelectric focusing (pH 3.5--5.0) to this system, we found a common variant, Pi M3, with an isoelectric point between those of Pi M1 and Pi M2. The gene frequency of this variant was .11 in U.S. whites and .054 in blacks. When PiM3 and PiM1 are included in the Pi system, the heterozygosity at the Pi locus is five times greater in whites and 10 times greater in blacks than that detected by earlier electrophoretic techniques.     

Characterization of alpha-1-antitrypsin by isoelectric focusing on an ultrathin polyacrylamide gel layer

Summary Through the use of ultrathin layer polyacrylamide gel isoelectric focusing it is possible to obtain a resolution of the bands of ₁AT so as to be able to easily recognize all six PiM subtypes. The optimal resolution of the PiM subtypes is obtained without deforming the pattern of the Pi phenotypes. In addition to high resolution, ultrathin layer polyacrylamide gel isoelectric focusing permits a notable reduction of fees to 1/5 of the usual.     

Reliable classification of six Pi M subtypes by separator isoelectric focusing.

For the first time, segregation of three common PiM alleles in family material is verified by application of separator isoelectric focusing. A new nomenclature system for the Pi M subtypes is used, whereby the common subtypes are designated according to their physicochemical properties; the most anodal type is called Pi M1, the intermediary one Pi M2, and the most cathodal variant Pi M3 (previously called Pi M2). Pi gene frequencies from Finnish, Dutch and Black populations are presented. The PiM2 allele was rather high in Finns (0.12) but low (0.04) in the West African Bozo. The PiM3 was found with a frequency of 0.13 in Dutch, 0.08 in Finns and 0.02 in Bozo. A previous Finnish sample was retested with the new subtyping method and the six-subtype distribution was found to be in good Hardy-Weinberg equilibrium. The validity of the Pi polymorphism for population genetics, linkage analysis and parentage testing is discussed.     

An alpha 1-antitrypsin variant, Pi B Alhambra (Lys to Asp, Glu to Asp), with rapid anodal electrophoretic mobility.

A variant of human alpha 1-antitrypsin (alpha 1 AT) was found by acid starch gel electrophoresis and by thin-layer electrofocusing. The variant has an anodal migration velocity almost identical to PiB. It is designated as Pi B Alhambra. Pi B Alhambra was purified to homogeneity from a heterozygous PiM1/PiB Alhambra subject. Specific trypsin inhibitory activity and composition of amino acids and carbohydrates were similar to those of normal PiM1. The structural difference between the normal and the variant inhibitors was elucidated by peptide mapping of their tryptic digests. Two amino acid substitutions, Lys to Asp and Glu to Asp, were found. The amino acid substitution, Gly to Asp, has been found in a common PiM2 variant [1]. The Pi B Alhambra variant presumably originated by two steps of mutation: generation of PiM2 from wild type PiM1 by the substitution Gly to Asp, and subsequent generation of Pi B Alhambra from PiM2 by another substitution, Lys to Asp.     

Genetic polymorphism of the alpha 1-antitrypsin system in the native population of the Kazakh SSR

Phenotypes of alpha 1-antitrypsin of 218 natives from three ethno-historical regions of the Kazakh SSR were detected by isoelectric focusing in ultrathin layer polyacrylamide gel. Gene frequencies of the PiM1, PiM2, PiM3 subtypes in the summary extract were as follows: 0.8477, 0.1372 and 0.0106, respectively; the total gene frequency of two rare variants (PiN and PiZ) was 0.0046. The observed distribution of Pi subtypes shows good agreement with the Hardi-Weinberg equation. The analysis of the interpopulation intraethnic variability of the alpha 1-antitrypsin phenotype and allele frequencies in Kazakhs revealed clear local diversity. The frequency of PiM1 in the natives from North-Central ethno-historical region was reliably lower and that of PiM2 higher than in populations from South-East and West regions. The extracts analysed did not differ in the PiM3 incidences. The results of these studies were compared with the literature data for alpha 1-antitrypsin polymorphism in populations of the Euro-Asia. It is shown that PiM1 and PiM2 frequencies in the Kazakhs differ from the corresponding mean values both in mongoloid and europeoid groups. At the same time, they do not correspond to the intermediate frequency estimations, which could be expected from the fact of mixed origin of the Kazakh people and their border-line geographical position between Europe and Asia. Possible reason for such discrepancy is discussed.     

alpha1-antitrypsin: common subtypes of Pi M.

More than 20 different alleles are so far known at the Pi locus, corresponding to a total variant phenotype frequency of about 10% in most western Europeans. The common phenotype Pi M constitutes the remaining major group. Now it has been possible to identify three subtypes M1, M1M2 and M2, corresponding to the gene products of two common alleles PiM1 and PiM2, segregating as autosomal codominant alleles. Preliminary gene frequencies are reported for eight populations, the PiM2 frequency varying from 0.20 in Maris (USSR) to 0.02 in Bantus (Kenya).     

Structural difference between the normal PiM1 and the common PiM2 variant of human alpha 1-antitrypsin.

The common PiM2 variant of human alpha 1-antitrypsin (alpha 1-AT) which can be distinguished from the wild type PiM1 by isoelectric focusing (IEF) in a narrow pH gradient, was purified to homogeneity from plasma of a homozygous PiM2/PiM2 subject. The specific trypsin inhibitory activity and the amino acid and carbohydrate composition of the normal PiM1 and the variant PiM2 are very similar. The structural difference between the normal and the variant inhibitors was elucidated by peptide mapping of their tryptic digests. An amino acid substitution of glutamic acid in the normal inhibitor by aspartic acid in the variant inhibitor was found. The same amino acid substitution was found in PiMN, which was presumed to be identical to PiM2 based on their IEF patterns.     

α1 (Pi) types and subtypes in the Tyrolean population

Since nine patients with infantile liver cirrhosis or hepatopathy associated with the Pi ZZ phenotype had been observed in recent years in the Children's Hospital of the University of Innsbruck, Tyrol, the distribution of the Pi types and the PiM subtypes was determined in the Tyrolean population. Apparently healthy blood donors (868) from different regions of Tyrol were examined. Isoelectricfocusing was used for classification of Pi types. The frequency of the allele PiZ was 0.0138, which corresponded to the range observed in other Middle European populations. The frequencies for the suballeles of PiM were PiM1 = 0.7062, PiM2 = 0.1480, and PiM3 = 0.1037. PiS had a frequency of 0.0225, the other rare alleles occurred with a combined frequency of 0.0058.     

Alpha 1 antitrypsin deficiency: a study of the relationship between the Pi system and genetic markers.

Twenty-four members (4 generations) of a family with alpha 1 antitrypsin deficiency were studied in an attempt to determine the chromosomal location of the Pi system locus. Three alpha 1 antitrypsin alleles (PiM, PiI, and PiZ) and five phenotypes (MM, MZ, MI, IZ, and ZZ) were detected in family members. The quinacrine fluorescent banding technique was successfully utilized to reveal eight polymorphic chromosomal markers in family members. Eight red cell antigens and HL-A antigens were identified for each family member. No linkage between the Pi system and chromosomal markers, four polymorphic red cell antigens, and HL-A antigens was detected. On the basis of this family study, the Pi locus as defined by alpha 1 antitrypsin deficiency does not appear to be on chromosomes 2, 3, 13, 14, 21, or 22 within measurable distance of the markers used.     

Alpha-1-antitrypsin: frequencies of PiM subtypes and serum concentration in the Japanese population

PiM subtypes were determined by isoelectric focusing of the sera of 746 Japanese at the age of 16-60 years. The gene frequencies were calculated: PiM1 = 0.7855, PiM2 = 0.1528 and PiM3 = 0.0617. The serum concentration of alpha-1-antitrypsin was measured by laser-nephelometric immunoassay of the sera of 284 individuals. A statistically significant difference (p less than 0.01) in the serum concentration was found between M1 (2.63 +/- 0.67 g/l) and M1M2 (2.39 +/- 0.59 g/l).     

Beta-Galactosidase immunoassay for the measurement of cyclic AMP

The previously described method for phenotyping of alpha₁-antitrypsin (alpha₁-protease inhibitor, Pi) that utilizes separator isoelectric focusing on thin-layer agarose gel (A. R. Qureshi and H. H. Punnett, in Electrophoresis '81, 3rd International Conference on Electrophoresis, pp. 83–87 (1981)) has been improved to give a better resolution of Pi pattern. A shallow pH gradient in the region of the isoelectric point of Pi pattern was obtained by the use of N-(2-acetamido)-2 aminoethanesulfonic acid (1%) and serine (0.8%). The present technique can resolve the Pi alleles. The patterns of Pi phenotypes were found to be similar to those observed on acrylamide gels. The method is fast, reliable, and reproducible.     

Genetic variants of serum alpha1-antitrypsin (Pi types) in Portuguese.

The results of Pi typing on 330 Portuguese from the area of Lisbon are reported. We found six phenotypes and four alleles out of the 24 described in the literature. The allele PiM is the most frequent as in other populations, PiS shows a high frequency (0.1152), and PiF is absent, which agrees satisfactorily with former studies carried out in Spain. These results are compared with others and the entity of the Iberian population is evoked.     

Classification of α 1-antitrypsin (Pi) phenotypes by isoelectrofocusing

Summary Pi phenotypes have been determined by isoelectrofocusing in a sample of 538 healthy individuals from Southern Germany. Further subdivision of the common PiM phenotype is described. A procedure for the delineation of six common subtypes is presented. It is assumed that the six subtypes are determined by three alleles which are provisionally called Pi^Ma, Pi^Mb, and Pi^Mc. Their frequencies in this sample were 0.75, 0.06, and 0.15, respectively.Supported in part by INSERM, contract No. AT-FA-58     

Polymorphism of alpha 1-antitrypsin in North American species of Canis

alpha 1-Antitrypsin (A1AT) is a major protease inhibitor present in all mammalian sera that have thus far been investigated. A1AT is also highly polymorphic and is therefore a useful genetic marker. Previously reported A1AT polymorphism in domestic dogs consisted of two alleles designated as PiM and PiS which exhibited frequencies of 0.72 and 0.28, respectively, in a group of randomly collected mongrel dogs. North American species of Canis, which included gray wolves (n = 29), Mexican wolves (n = 20), coyotes (n = 24), wolf-dog crosses (n = 9), and red wolves (n = 27) were tested for A1AT polymorphism. A1AT phenotypes were determined by isoelectric focusing, followed by direct immunoblotting using a specific antiserum. A1AT concentrations were determined by radial immunodiffusion. Concentrations of A1AT were similar to those found in domestic dogs (2.26 +/- 0.3, +/- SD mg/ml, +/- SD) and tended to be higher in females than in males, possibly indicating that A1AT may be hormonally influenced in females. Three phenotypic band patterns were observed (M, MS, S). The allele frequencies for domestic dogs and gray wolves were very similar, 0.72 and 0.67 for PiM and 0.28 and 0.33 for PiS, respectively. The Mexican wolves had a significantly lower frequency of PiS = 0.10. Coyotes and red wolves were all found to be monomorphic for the PiS allele and were indistinguishable from each other in that respect.     

alpha 1-Antitrypsin quantitative and qualitative (Pi phenotyping) characterization in Down syndrome subjects and in their parents.

Quantitative characterization and alpha 1-antitrypsin (alpha 1AT) Pi phenotyping by isoelectric focusing (IEF) and immunofixation electrophoresis (IFE) were done on 84 patients with trisomy 21, divided into two groups, and on their parents. Group A consisted of 42 subjects whose parents were less than 30 years at the time of the patient's birth; group B, of 42 subjects whose parents were more than 35 years. The results were compared with those found in a group of normal subjects. Statistical analysis of the Pi phenotype distribution and the frequency of variant phenotypes does not support a causal relationship between the Pi phenotype and the chromosomal errors responsible for Down syndrome.