title: Single-nucleotide polymorphisms in genes involved in placental function and unexplained stillbirth.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the association between unexplained stillbirth (SB) and single-nucleotide polymorphisms (SNPs) in genes involved in placental function using a well-characterized cohort.
  
  
  METHODS
  Placentas were obtained from 50 unexplained SB and 46 live birth controls. Classification of stillbirth was by Wigglesworth criteria. SBs were stratified by weight: appropriate (AGA-SB) and small for gestational age (SGA-SB, less than the 10th percentile) and gestational age: before 32 and after 32 weeks. Placental DNA was extracted and various SNPs in the endothelial nitric oxide synthase (eNOS), Klotho, hypoxic inducible factor-1α, and and tumor necrosis factor-α genes were evaluated.
  
  
  RESULTS
  None of the SNPs were associated with SB overall. Significantly different genotype distribution emerged for eNOS-SNP rs1800783 when comparing AGA-SB with SGA-SB and control (P = .004). Its allele-A was more frequent in AGA-SB compared with both controls (P = .03) and SGA-SB (P = .001). No differences were seen accordingly to gestational age.
  
  
  CONCLUSIONS
  Unexplained stillbirth in the setting of adequate growth is associated with carrier of allele A of rs1800783 eNOS gene in the placenta.
authors.affiliation: Division of Maternal-Fetal Medicine, Mother-Infant Department, University of Modena and Reggio Emilia, Modena, Italy. ferrari196@yahoo.com
authors.forename: Francesca
authors.initials: F
authors.lastname: Ferrari
authors.forename: Fabio
authors.initials: F
authors.lastname: Facchinetti
authors.forename: Huaizhi
authors.initials: H
authors.lastname: Yin
authors.forename: George R
authors.initials: GR
authors.lastname: Saade
authors.forename: Monica
authors.initials: M
authors.lastname: Longo
mesh_terms: D000328:Adult; D000483:Alleles; D005260:Female; D005838:Genotype; D005966:Glucuronidase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics* / Q000378:metabolism; D000090265:Klotho Proteins; D052250:Nitric Oxide Synthase Type III / Q000235:genetics* / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D011247:Pregnancy; D050497:Stillbirth / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics* / Q000378:metabolism
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D014409:Tumor Necrosis Factor-alpha; D052250:Nitric Oxide Synthase Type III; D005966:Glucuronidase; D000090265:Klotho Proteins