title: The effects of metallothionein 2A polymorphism on lead metabolism: are pregnant women with a heterozygote genotype for metallothionein 2A polymorphism and their newborns at risk of having higher blood lead levels?
abstract: OBJECTIVE
  Numerous studies indicate that certain genetic polymorphisms modify lead toxicokinetics. Metallothioneins are protective against the toxicity of many metals, including lead. The aim of this study was to determine whether the maternal metallothionein 2A (MT2A) -5 A/G single-nucleotide polymorphism is related to the lead levels in maternal blood, placental tissue and cord blood in 91 pregnant women and their newborns.
  
  
  METHODS
  Venous blood from the mother was collected to investigate lead levels and MT2A polymorphism. Cord blood and placenta were collected for lead levels. Analyses were made using an Atomic Absorption Graphite Furnace Spectrophotometer. Standard PCR-RFLP technique was used to determine MT2A polymorphism.
  
  
  RESULTS
  Blood lead levels of heterozygote genotype (AG) mothers were statistically higher than those of homozygote genotype (AA) (P < 0.05). Maternal lead levels were significantly associated with cord blood lead levels for pregnant women with AA genotype (P < 0.001). This association was not statistically significant for pregnant women with AG. In contrast, the mean value of cord blood lead level for newborns with mothers of AG genotype was slightly higher than others, though the difference was not significant. No significant difference existed in placenta lead levels between the groups.
  
  
  CONCLUSIONS
  This study suggests that pregnant women with AG genotype for MT2A polymorphism might have high blood lead levels and their newborns may be at risk of low-level cord blood lead variation.
authors: Institute of Forensic Sciences, Ankara University, Dikimevi, 06590, Ankara, Turkey. drdeniztekin@yahoo.com
authors: Deniz
authors: D
authors: Tekin
authors: Zeliha
authors: Z
authors: Kayaaltı
authors: Tülin
authors: T
authors: Söylemezoğlu
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005312:Fetal Blood; D006579:Heterozygote; D006801:Humans; D007231:Infant, Newborn; D007854:Lead / Q000097:blood*; D008668:Metallothionein / Q000235:genetics* / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011247:Pregnancy; D018570:Risk Assessment; D014421:Turkey; D055815:Young Adult
chemical_list: C491053:MT2A protein, human; D007854:Lead; D008668:Metallothionein