Lack of association of delta-aminolevulinate dehydratase polymorphisms with blood lead levels and hemoglobin in Romanian women from a lead-contaminated region.

As part of a project on environmental pollution, this study aimed to evaluate associations between blood lead (BPb) levels, hemoglobin (Hb) content, and single-nucleotide polymorphisms (SNPs) of delta-aminolevulinic acid dehydratase (ALAD) gene in 129 unrelated women from Romania. Five SNPs (rs1805313, rs2228083, rs1805312, rs1800435, rs1139488) were analyzed with respect to haplotype structure and impact on BPb levels and Hb content with proportional odds and analysis of covariance models. Combinations of SNPs were rare (16%). Low haplotype diversity was found with seven haplotypes. One rare haplotype implied the C allele of rs1800435, often referred to as the ALAD2 allele (frequency 8.6%). The putative risk genotype (CC) occurred in only one woman with BPb below 0.5 microg/dl. Median BPb was 4.8 microg/dl and differed markedly by community with a level of 12.5 microg/dl near a mining-spill region. Hb was regular (interquartile range 12.3-13.7 g/dl) and not correlated with BPb, although quantitatively lower in women living near the spill region. No significant associations were found for BPb or Hb with SNPs, haplotypes, or diplotypes. BPb levels were higher in this region than in populations from industrialized countries but without hematotoxic effects. An impact of ALAD2 on BPb or Hb was not seen in these women.

Occupational exposure to endocrine-disrupting compounds and biliary tract cancer among men.

OBJECTIVES: This study investigated the association between cancer of the extrahepatic biliary tract and exposure to endocrine-disrupting compounds. METHODS: Altogether 183 men with histologically confirmed carcinoma of the extrahepatic biliary tract and 1938 matched controls were interviewed between 1995 and 1997 in the frame of an international multicenter case-control study in six European countries (Denmark, France, Germany, Italy, Spain, and Sweden). Self-reported job descriptions were converted to semiquantitative variables (intensity, probability, and duration of exposure) for 14 endocrine-disrupting compounds. The cases were compared with 1421 population controls and 517 colon adenocarcinoma patients. Odds ratios (OR) and 95% confidence intervals (95% CI) were obtained with unconditional logistic regression and adjusted for age, country, and gallstones. RESULTS: Occupational exposure to endocrine-disrupting compounds resulted in an OR of 1.4 (95% CI 1.0-2.1) with no dose-effect relationship for cumulative exposure (low: OR 1.3, 95% CI 0.6-3.0; medium: OR 1.5, 95% CI 0.8-2.7; high: OR 1.4, 95% CI 0.9-2.4) (only index participants). The elevated risk was restricted to extrahepatic bile ducts and ampulla Vateri (OR 1.7, 95% CI 1.0-2.6). The adjusted OR for cancer of the extrahepatic biliary tract after exposure to polychlorinated biphenyls was 2.8 (95% CI 1.3-5.9, only index participants). CONCLUSIONS: The data show some associations between exposure to endocrine-disrupting compounds in the workplace and the risk for cancer of the extrahepatic biliary tract among men, particularly for the extrahepatic bile duct and ampulla of Vater. Polychlorinated biphenyls could possibly be a strong risk factor.

Variation of the N-acetyltransferase 2 gene in a Romanian and a Kyrgyz population.

As part of a project on environmental disasters in minority populations, this study aimed to evaluate differences in the sequence of N-acetyltransferase 2 (NAT2) as a metabolic susceptibility gene in yet unexplored ethnicities. Eight single nucleotide polymorphisms (SNP) in the NAT2 coding region and a variant in the 3' flanking region were analyzed in 290 unrelated Kyrgyz and 140 unrelated Romanians by SNP-specific PCR analysis. The variants 341C, 481T, and 803G were less and 857A more prevalent in Kyrgyz (P < 0.0001). The variant at site 857 indicates Asian descent. 282C>T and 590G>A showed no significant variation by ethnicity. 364G>A and 411A>T turned out to be monomorphic. Database comparisons of the NAT2 minor allele frequencies support that Romanians belong to Caucasians and Kyrgyz are in between Caucasians and East Asians. The distributions of predicted haplotypes differed significantly between the two ethnicities where the Kyrgyz showed a higher genetic diversity. The haplotype without mutations was more common in Kyrgyz (40.1% in Kyrgyz, 29.3% in Romanians). Accordingly, the imputed slow acetylator phenotype was less prevalent in Kyrgyz (35.2% versus 51.4% in Romanians). We found pronounced ethnic differences in NAT2 genotypes with yet unknown effect on the health risks for environmental or occupational exposures in minority populations.

Glutathione S transferase theta 1 gene (GSTT1) null genotype is associated with an increased risk for acquired aplastic anemia in children.

Two main factors have been implicated in the mechanism underlying the pathogenesis of acquired aplastic anemia: environmental factors and genetic susceptibility. Individuals vary in their ability to metabolize several DNA-damaging agents due to polymorphisms of biotransforming enzymes. Genetically determined differences in the expression of these enzymes could explain interindividual risks in developing acquired aplastic anemia. The aim of the study was to characterize the genetic polymorphism of biotransforming phase I (p450-cyp2E1) and phase II [microsomal epoxide hydrolase (mEh), glutathione S-transferase (GST)] enzymes in pediatric patients with acquired aplastic anemia. The GSTT1 null genotype (absence of both alleles) was associated with a significantly increased risk for acquired aplastic anemia (odds ratio, 2.8; 95% confidence interval, 0.15-5.7). In contrast, the GSTM1 null genotype or polymorphisms within the p450-cyp2E1 and mEh genes was not significantly different in patients and controls. Multivariate analysis was performed to assess whether the enzymes together or with other variables as age, gender, or response to therapy may have any significant association with the tested genotypes. In no combinations of the mentioned parameters was an association found with acquired aplastic anemia. GST are mainly involved in metabolizing hematotoxic and mutagenic substrates such as benzene derivatives. The GSTT1 null genotype may modulate the metabolism of exogenous pollutants or toxic intermediates. The absence of the GSTT1 enzyme, leading to genetic susceptibility toward certain pollutants, might determine the individual risk for development of acquired aplastic anemia in children.