title: Abnormal DNA Methylation of Imprinted Loci in Human Preimplantation Embryos.
abstract: OBJECTIVE
  To evaluate the epigenetic risk linked to assisted reproductive technology (ART) at single-embryo level by analyzing the methylation status of imprinted H19, PEG1, and KvDMR1 in human preimplantation embryos.
  
  
  METHODS
  A total of 254 human day 3 embryos produced by ART procedures were collected. All embryos were normally fertilized but unsuitable for transfer or freezing due to poor quality. Pyrosequencing with confirmatory routine bisulfite sequencing were used to determine the DNA methylation patterns of H19 differentially methylated region (DMR) in 63 embryos, PEG1 DMR in 65 embryos, and KvDMR1 in 67 embryos.
  
  
  RESULTS
  Aberrant methylation patterns were found in 8.0% embryos at H19 DMR, 16.9% embryos at PEG1 DMR, and 10.4% embryos at KvDMR1. No methylation errors were found in corresponding sperm samples.
  
  
  CONCLUSIONS
  We hypothesized that the use of poor-quality embryos may increase the risk of imprinting defects because they might have methylation errors.
authors.affiliation: Departments of reproductive Medicine and Obstetrics and Gynecology, The Second People's Hospital of Guiyang, Guiyang, People's Republic of China guiyishi@163.com.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Shi
authors.affiliation: Department of Obstetrics and Gynecology, Center for reproductive Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China chensl_92@163.com.
authors.forename: Shiling
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Obstetrics and Gynecology, Center for reproductive Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Department of Obstetrics and Gynecology, Center for reproductive Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China.
authors.forename: Lele
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Obstetrics and Gynecology, Center for reproductive Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China.
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Wu
keywords: H19; KvDMR1; PEG1; human embryo; methylation