title: Maternal smoking and the risk of orofacial clefts: Susceptibility with NAT1 and NAT2 polymorphisms.
abstract: BACKGROUND
  Orofacial clefts are etiologically heterogeneous malformations. One probable cause is maternal smoking during pregnancy. The effect of maternal smoking may be modified by genes involved in biotransformation of toxic compounds derived from tobacco. We investigated whether polymorphic variants of fetal acetyl-N-transferases 1 (NAT1) and 2 (NAT2) interact with maternal cigarette smoking during early pregnancy to increase the risk of delivering an infant with an orofacial cleft.
  
  
  METHODS
  In a California population-based case-control study, we genotyped 421 infants born with an isolated cleft and 299 nonmal-formed controls for 2 NAT1 and 3 NAT2 single nucleotide polymorphisms
  
  
  RESULTS
  Although smoking was independently associated with increased risks for both isolated cleft lip +/- cleft palate and isolated cleft palate, no independent associations were found for NAT1 1088 or 1095 genotypes or for NAT2 acetylator status. However, the infant NAT1 1088 and 1095 polymorphisms were strongly associated with the risk of clefts among smoking mothers; infants with NAT1 1088 genotype AA versus TT (odds ratio [OR] = 3.9; 95% confidence interval = 1.1-17.2) and with NAT1 1095 genotype AA versus CC (OR = 4.2; 1.2-18.0). Infant NAT2 acetylator status did not appreciably affect susceptibility of the fetus to the teratogenic effects of maternal smoking.
  
  
  CONCLUSIONS
  Our results suggest that maternal smoking during pregnancy may increase risk for orofacial clefts particularly among smokers whose fetuses have polymorphic variants of NAT1, an enzyme involved in phase II detoxification of tobacco smoke constituents.
authors.affiliation: Children's Hospital Research Institute, 5700 Martin Luther King, Jr. Way, Oakland, CA 94609, USA. elammer@chori.org
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Lammer
authors.forename: Gary M
authors.initials: GM
authors.lastname: Shaw
authors.forename: David M
authors.initials: DM
authors.lastname: Iovannisci
authors.forename: Janee
authors.initials: J
authors.lastname: Van Waes
authors.forename: Richard H
authors.initials: RH
authors.lastname: Finnell
mesh_terms: D000123:Acetyltransferases / Q000235:genetics*; D000328:Adult; D002140:California; D005260:Female; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D007569:Jaw Abnormalities / Q000209:etiology* / Q000235:genetics; D011110:Polymorphism, Genetic; D011247:Pregnancy; D012306:Risk; D012907:Smoking / Q000009:adverse effects*; D011795:Surveys and Questionnaires
chemical_list: D000123:Acetyltransferases