title: Delta-aminolevulinic acid dehydratase (ALAD) polymorphism in lead exposed Bangladeshi children and its effect on urinary aminolevulinic acid (ALA).
abstract: OBJECTIVE
  Lead has long been recognized as a harmful environmental pollutant. People in developing countries like Bangladesh still have a higher risk of lead exposure. Previous research has suggested that the delta-aminolevulinic acid dehydratase (ALAD) genotype can modify lead toxicity and individual susceptibility. As children are more susceptible to lead-induced toxicity, this study investigated whether the ALAD genotype influenced urinary excretion of delta-aminolevulinic acid (U-ALA) among children exposed to environmental lead in Bangladesh.
  
  
  METHODS
  Subjects were elementary schoolchildren from a semi-urban industrialized area in Bangladesh. A total of 222 children were studied. Blood and urine were collected to determine ALAD genotypes, blood lead levels and urinary aminolevulinic acid (U-ALA).
  
  
  RESULTS
  The mean BPb level was 9.7 µg/dl for the study children. BPb was significantly positively correlated with hemoglobin (p<0.01). In total, allele frequency for ALAD 1 and 2 was 0.83 and 0.17 respectively. The mean U-ALA concentration was lower in ALAD1-2/2-2 carriers than ALAD1-1 carriers for boys (p=0.001). But for girls, U-ALA did not differ significantly by genotype (p=0.26). When U-ALA was compared by genotype at the same exposure level in a multiple linear regression analysis, boys who were ALAD1-2/2-2 carriers still had a lower level of U-ALA compared to ALAD1-1 carriers.
  
  
  CONCLUSIONS
  This study provides information about the influence of ALAD polymorphism and its association with U-ALA in Bangladeshi children. Our results indicate that the ALAD1-2/2-2 genotype may have a protective effect in terms of U-ALA for environmentally lead exposed boys.
authors.affiliation: Department of Human Ecology, School of International Health, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Electronic address: rimzim1612@yahoo.com.
authors.forename: Saira
authors.initials: S
authors.lastname: Tasmin
authors.affiliation: Department of Human Ecology, School of International Health, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Hana
authors.initials: H
authors.lastname: Furusawa
authors.affiliation: Department of Occupational and Environmental Health, Bangladesh Institute of Health Sciences, 125/1, Darus Salam, Mirpur, Dhaka 1216, Bangladesh.
authors.forename: Sk Akhtar
authors.initials: SA
authors.lastname: Ahmad
authors.affiliation: Department of Public Health, State University of Bangladesh, 77 Satmasjid Road, Dhanmondi, Dhaka 1205, Bangladesh.
authors.forename: M H
authors.initials: MH
authors.lastname: Faruquee
authors.affiliation: Department of Human Ecology, School of International Health, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Watanabe
mesh_terms: D000622:Aminolevulinic Acid / Q000652:urine*; D001459:Bangladesh; D001483:Base Sequence; D002648:Child; D017931:DNA Primers; D005260:Female; D005787:Gene Frequency; D006801:Humans; D007854:Lead / Q000633:toxicity*; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D000623:Porphobilinogen Synthase / Q000235:genetics*
chemical_list: D017931:DNA Primers; D007854:Lead; D000622:Aminolevulinic Acid; D000623:Porphobilinogen Synthase
keywords: ALAD polymorphism; Bangladesh; Blood lead level; Children; Urinary ALA