F.J. de Serres

Genetic epidemiology of alpha-1 antitrypsin deficiency in North America and Australia/New Zealand: Australia, Canada, New Zealand and the United States of America

Alpha‐1‐antitrypsin deficiency (AAT deficiency) is one of the most common serious hereditary disorders in the world, as its affects all major racial subgroups worldwide, and there are an estimated 120.5 million carriers and deficient subjects worldwide. This genetic disease is related to susceptibility for development of jaundice in infants, liver disease in children and adults and pulmonary emphysema in adults. Moreover, AAT deficiency carrier phenotypes (PiMS and PiMZ) and deficiency allele phenotypes (PiSS, PiSZ and PiZZ) are suspected to predispose subjects to a variety of other adverse health effects. Because there is a limited database on the number of individuals affected by this disease worldwide, we have collected data on control cohorts in genetic epidemiological studies published on case–control studies in the peer‐reviewed literature worldwide. Based on these data, we estimated the numbers of carriers and deficiency allele combinations for the two most common defective alleles, namely PiS and PiZ in 58 countries worldwide. The present paper focuses on the distribution of the PiS and PiZ deficiency alleles in Australia, Canada, New Zealand and the United States of America. A total of 31,042,232 individuals at risk for adverse health effects have been calculated in these four countries: 2,144,158 in Australia, 3,258,564 in Canada, 430,922 in New Zealand and 24,909,548 in the United States of America. The prevalences for all five phenotypic classes of AAT deficiency in each of these countries is as follows: Australia 1 out of 8.9, Canada 1 out of 9.8, New Zealand 1 out of 8.5 and the United States of America 1 out of 11.3. The geographical distribution of individual control cohorts and estimates of the numbers of carriers and deficiency allele phenotypes in each of these four countries are given in individual tables.

Genetic epidemiology of alpha‐1 antitrypsin deficiency in southern Europe: France, Italy, Portugal and Spain

Alpha‐1‐antitrypsin deficiency (AAT deficiency) is one of the most common serious hereditary disorders in the world because it affects all major racial subgroups worldwide and there are at least 120.5 million carriers and deficient subjects worldwide. This genetic disease is related to a high risk for development of jaundice in infants, liver disease in children and adults, and pulmonary emphysema in adults. Moreover, AAT‐deficiency carrier phenotypes (PiMS and PiMZ) and deficiency‐allele phenotypes (PiSS, PiSZ, and PiZZ) are suspected to make subjects susceptible to a variety of other adverse health effects. As there is a limited database on the number of individuals affected by this disease worldwide, the authors of the present report collected data on control cohorts in genetic epidemiological studies published in the peer‐reviewed literature worldwide. The data collected were used to estimate the numbers of carriers and deficiency‐allele combinations for the two most common defective alleles, namely PiS and PiZ, in over 58 countries worldwide. The present report focuses on the distribution of the PiS and PiZ deficiency alleles in France, Italy, Portugal, and Spain. The total number of individuals at risk for adverse health effects were as follows: 9, 101, 739 in France; 4, 289, 566 in Italy; 2, 659, 241 in Portugal; and 8, 903, 773 in Spain. The geographical distribution of individual control cohorts and estimates of the numbers of carriers and deficiency‐allele phenotypes in each of these four southern European countries are shown in individual tables and maps. This report will be followed by other reports on the remaining countries in Europe, as well as worldwide.

Results and recommendations

Abstract In the first phase of a collaborative study by the International Programme on Chemical Safety (PRCS), four coded chemicals, i.e. azidoglycerol (AG, 3-azido-1,2-propanediol), methyl nitrosurea (MNU), sodium azide (NaN 3 ) and maleic hydrazide (MH), and ethyl methanesulfonate (EMS) as a positive control were tested in four plant bioassays, namely the Arabidopsis embryo and chlorophyll mutation assay, the Tradescantia stamen hair assay (Trad-SH assay), the Tradescantia micronucleus assay (Trade-MCN), and the Vicia faba root tip assay. Seventeen laboratories from diverse regions of the world participated with four to six laboratories each using one plant assay. For the Arabidopsis assay, laboratories were in agreement with MNU and AG giving positive responses and NaN 3 giving a negative response. With the exception of one laboratory which reported MH as weakly mutagenic, no mutagenic response was reported for MH by the other laboratories. For the Vicia faba assay, all laboratories reported a positive response for MNU, AG, and MH, whereas two of the six laboratories reported a negative response for NaN 3 . For the Trad-SH assay, MH was reported as giving a positive response and a positive response was also observed for MNU with the exception of one laboratory. NaN 3 , which exhibited a relatively high degree of toxicity, elicited a positive response in three of the five laboratories. AG was found positive in only one of the two laboratories which tested this chemical. For the Trad-MCN assay, MNU and MH were reported as positive by all laboratories, while four out of five laboratories reported NaN 3 to be positive. Only one of three laboratories reported AG to be positive. The major sources of variability were identified and considered to be in the same range as found in similar studies on other test systems. Recommendations were made for minor changes in methodology and for initiating the second phase of this study.

Mutagenesis at the ad-3A and ad-3B loci in haploid UV-sensitive strains of Neurospora crassa: I. Development of isogenic strains and spontaneous mutability

7 different mutations that confer sensitivity to inactivation by ultraviolet light have been investigated for their effect on spontaneous mutation at the ad-3A and ad-3B loci in haploid strains of Neurospora crassa. The collection and development of strains isogenic to wild-type 74A is described as well as experiments to determine the effects of each mutation on the spontaneous ad-3 mutation frequency. 6 of the strains showed spontaneous ad-3 mutant frequencies not significantly different from the wild-type strain. Strain uvs-3 is highly mutable spontaneously with marked variation from experiment to experiment; the mean mutation frequency in this strain in about 40-fold higher than that found in the wild-type strain.

A report of the U.S. environmental protection agency gene-tox program: Evaluation of mutagenicity assays for purposes of genetic risk assessment☆

For the vast majority of chemicals, mammalian germ-line (MG) mutation data do not exist. The question was examined of how best to utilize results of non-MG genotoxicity assays that are included in the Gene-Tox data base to provide information of the likelihood that genetic damage might be induced in and transmitted by the reproductive cells of exposed human beings. Two approaches were used to assess the relative value of different assays for genetic hazard identification. (1) Test results were weighted according to parameters by which conditions of an assay resemble those encountered in the potential induction of transmitted genetic damage in mammals. For this purpose, 35 assays were grouped into 16 categories that were assigned weights ranging from 1 to 15; there were 2367 chemicals in the data base. This system was evaluated by comparing the sum of weighted test results for each chemical with the outcome of MG-standard (MGst) tests where such had been reported. (MGst tests used were the specific-locus and heritable-translocation assays [SLT and HTT] for gene mutations and chromosome aberrations, respectively.) The weighting system produced a few false positives with respect to the MGst results. It produced no false negatives, but the available evidence is limited by the circumstance that MGst test have evidently been preferentially performed with chemicals that had already been shown to be positive in several other assays. (2) Findings from each MGst test were compared with those from each of the other assays in turn, provided that at least 10 chemicals had been tested in both of the assays. There were 11 such comparisons involving the SLT, and 14 such comparisons involving the HTT. The observed concordance was above random expectation in several comparisons, particularly those involving certain mammalian in vivo tests, but in only one case (HTT vs. unscheduled DNA synthesis in the testis) did the degree of elevation approach statistical significance.

Mutagenesis at the ad-3A and ad-3B loci in haploid UV-sensitive strains of Neurospora crassa: V. Comparison of dose-response curves of single- and double-mutant strains with wild-type

The interactions of mutant alleles that individually confer radiation sensitivity in Neurospora crassa are being studied with regard to their effects on radiation-induced inactivation and forward-mutation induction at the ad-3 loci. This paper reports attempts to construct 3 double-mutant strains containing the following pair-wise combinations of repair-deficient mutants: upr-1,uvs-2; uvs-2,uvs-6; and uvs-3,uvs-6. The double-mutant strain with the 2 excision-repair-deficient mutants upr-1 and uvs-2 shows increased sensitivity to X-ray-induced mutagenesis and inactivation, relative to that shown by either of the parental single-mutant strains. This double mutant is no more sensitive than the parental single-mutant strains to either UV mutagenesis or inactivation. The combination of the uvs-2 and uvs-6 double-mutant strain is considerably more sensitive to both UV and X-ray inactivation than either the uvs-2 or uvs-6 strain, but it shows no greater sensitivity than the parental strains to ad-3 mutation induction by either agent. The combination of the uvs-3 and uvs-6 alleles is inviable. Tetrad analysis and microscopical examination of ascospores shows that ascospores of presumptive genotype uvs-3, uvs-6 do not grow beyond the formation of a few hyphal threads. The lethal and mutagenic effects of UV and X-irradiation in these double-mutant strains are interpreted in terms of the repair systems in Neurospora and other microorganisms.

Mutagenesis at the ad-3A and ad-3B loci in haploid UV-sensitive strains of Neurospora crassa IV. Comparison of dose—response curves for MNNG, 4NQO and ICR-170 induced inactivation and the mutation-induction

The genetic effects of MNNG, 4NQO and ICR-170 have been compared on 5 different UV-sensitive strains and a standard wild-type strain of Neurospora crassa with regard to inactivation and the induction of forward-mutations at the ad-3A and ad-3B loci. Whereas all UV-sensitive strains (upr-1, uvs-2, uvs-3, uvs-5 and uvs-6) are more sensitive to inactivation by MNNG and ICR-170 than wild-type, only uvs-5 shows survival comparable to wild-type after 4NQO treatment, all other strains are more sensitive to 4NQO. In contrast to the effects on inactivation, a wide variety of effects were found for the induction of ad-3A and ad-3B mutations: higher forward-mutation frequencies than were found in wild-type were obtained after treatment with MNNG or 4NQO for upr-1 and uvs-2, no significant increase over the spontaneous mutation frequency was found with uvs-3 after MNNG, 4NQO or ICR-170 treatment; mutation frequencies comparable to that found in wild-type were obtained with uvs-6 after MNNG, 4NQO or ICR-170 treatment and with upr-1 after ICR-170 treatment. Lower forward-mutation frequencies than were found in wild-type were obtained with uvs-2 after ICR-170 treatment and with uvs-5 after MNNG, 4NQO or ICR-170 treatment. These data clearly show that the process of forward-mutation at the ad-3A and ad-3B loci is under genetic control by mutations at other loci (e.g. upr-1, uvs-2, uvs-3, uvs-5 and uvs-6) and that the effect is markedly mutagen-dependent.

Two N-hydroxylaminopurines are highly mutagenic in the ad-3 forward-mutation test in growing cultures of heterokaryon 12 of Neutospora crassa

3 purine analogs were tested for their mutagenic activities in the ad-3 forward-mutation test in heterokaryon 12 (H-12) of Neurospora crassa. In growing cultures of H-12, the N-hydroxylaminopurines 2-amino-6-N-hydroxylaminopurine (AHA) and 6-N-hydroxylaminopurine (HAP) are potent and strong mutagens, respectively, whereas 2-aminopurine (AP) is a weak mutagen. AHA and HAP are about equally mutagenic at low doses, but AHA is more mutagenic than HAP at high doses. Despite their potent mutagenicity in growing cultures, AHA and HAP are not mutagenic in nongrowing conidia under the conditions of our experiments. AHA is the most potent mutagen tested in the ad-3 forward-mutation test in N. crassa. At the highest dose tested (30 micrograms/ml), it gave an ad-3 mutant frequency of 0.7 X 10(-2), about a 12,000-fold increase over the average spontaneous ad-3 mutant frequency. The potent mutagenicity of AHA may make it (and possibly HAP) especially useful for obtaining specific-locus mutations in other organisms.

Genetic characterization of ad-3 mutants induced by chemical carcinogens, 1-phenyl-3-monomethyltriazene and 1-phenyl-3,3-dimethyltriazene, in Neurospora crassa

Abstract 180 ad-3 mutants of Neurospora crassa induced by 1-phenyl-3-monomethyl-triazene (PMMT) and 56 ad-3 mutants induced by 1-phenyl-3,3-dimethyltriazene (PDMT) were characterized by dikaryon, trikaryon and complementation tests. Results show that the spectrum of genetic alterations induced by PMMT is different from that of PDMT. This suggests that enzymatic dealkylation of PDMT to PMMT does not occur within Neuropsora crassa conidia, and that the mechanism of mutation induction of PDMT in N. crassa is different from that of PMMT. Hydrolytic breakdown products or its intact molecule or some other converted forms might be responsible for the mutagenic activity of PDMT. Mutation induction of PMMT in N. crassa appears to be via alkylation of DNA by carbonium ions produced by this compound, the same mechanism proposed for its carcinogenic activity. The frequencies of leakiness, allelic complementation and nonpolarized complementation patterns among PMMT-induced ad-3 mutants are similar to those of ad-3 mutants induced by other potent chemical carcinogens, such as MNNG and the aflatoxins.

The efficacy of neurospora in detecting agents that cause aneuploidy

A total of 110 agents, 109 chemicals plus gamma-rays, has been tested in a Neurospora pseudowild-type selection system for their ability to induce meiotic aneuploidy. 11 agents were positive, 47 were negative, and 52 were inconclusively tested. The system has a possible role as a short-term test for environmental agents causing human aneuploidy. The advantages of the system are its simplicity and ease of use. Disadvantages are its high variability of aneuploid frequency and an inability to distinguish mechanisms of aneuploidy.