title: Influence of glutathione S-transferase polymorphisms on cognitive functioning effects induced by p,p'-DDT among preschoolers.
abstract: BACKGROUND
  Early-life exposure to p,p'-DDT [2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane] is associated with a decrease in cognitive skills among preschoolers at 4 years of age. We hypothesized that genetic variability in glutathione S-transferase (GST) genes (GSTP1, GSTM1, and GSTT1) could influence the effects of prenatal exposure to p,p'-DDT.
  
  
  METHODS
  We used data from 326 children assessed in a prospective population-based birth cohort at the age of 4 years. In that study, the McCarthy Scales of Children's Abilities were administrated by psychologists, organochlorine compounds were measured in cord serum, and genotyping was conducted for the coding variant Ile105Val from GSTP1 and for null alleles from GSTM1 and GSTT1. We used linear regression models to measure the association between organochlorines and neurodevelopmental scores by GST polymorphisms.
  
  
  RESULTS
  p,p'-DDT cord serum concentration was inversely associated with general cognitive, memory, quantitative, and verbal skills, as well as executive function and working memory, in children who had any GSTP1 Val-105 allele. GSTP1 polymorphisms and prenatal p,p'-DDT exposure showed a statistically significant interaction for general cognitive skills (p = 0.05), quantitative skills (p = 0.02), executive function (p = 0.01), and working memory (p = 0.02). There were no significant associations between p,p'-DDT and cognitive functioning at 4 years of age according to GSTM1 and GSTT1 polymorphisms.
  
  
  CONCLUSIONS
  Results indicate that children with GSTP1 Val-105 allele were at higher risk of the adverse cognitive functioning effects of prenatal p,p'-DDT exposure.
authors.affiliation: Center for Research in Environmental Epidemiology, Barcelona, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Morales
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.forename: Francesc
authors.initials: F
authors.lastname: Castro-Giner
authors.forename: Xavier
authors.initials: X
authors.lastname: Estivill
authors.forename: Jordi
authors.initials: J
authors.lastname: Julvez
authors.forename: Nuria
authors.initials: N
authors.lastname: Ribas-Fitó
authors.forename: Maties
authors.initials: M
authors.lastname: Torrent
authors.forename: Joan O
authors.initials: JO
authors.lastname: Grimalt
authors.forename: Rafael
authors.initials: R
authors.lastname: de Cid
mesh_terms: D002675:Child, Preschool; D003071:Cognition / Q000187:drug effects*; D015331:Cohort Studies; D003634:DDT / Q000633:toxicity*; D005260:Female; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011110:Polymorphism, Genetic
chemical_list: D003634:DDT; D005982:Glutathione Transferase