title: DNA methylation aberrations rather than polymorphisms of FZD3 gene increase the risk of spina bifida in a high-risk region for neural tube defects.
abstract: BACKGROUND
  Animal models of neural tube defects (NTDs) have indicated roles for the Fzd3 gene and the planar cell polarity signaling pathway in convergent extension. We investigated the involvement of FZD3 in genetic and epigenetic mechanisms associated with human NTDs, especially spina bifida. We explored the effects of variants spanning the FZD3 gene in NTDs and examined the role of aberrant methylation of the FZD3 promoter on gene expression in brain tissue in spina bifida.
  
  
  METHODS
  Six FZD3 single nucleotide polymorphisms were genotyped using a MassARRAY system in tissue from 165 NTD fetuses and 152 controls. DNA methylation aberrations in the FZD3 promoter region were detected using a MassARRAY EpiTYPER (17 CpG units from -500 to -2400 bp from the transcription start site) in brain tissue from 77 spina bifida and 74 control fetuses.
  
  
  RESULTS
  None of the six single nucleotide polymorphisms evaluated were significantly associated with spina bifida, but the mean methylation level was significantly higher in spina bifida samples (13.70%) compared with control samples (10.91%) (p = 0.001). In terms of specific sites, DNA methylation levels were significantly higher in the spina bifida samples at 14 of the 17 CpG units, which mostly included in R2 region. FZD3 mRNA expression was negatively correlated with methylation of the FZD3 promoter region, especially the R2 region (R = 0.970; p = 0.001) in HeLa cells.
  
  
  CONCLUSIONS
  The results of this study suggest that DNA methylation plays an important role in FZD3 gene expression regulation and may be associated with an increased risk of spina bifida.
authors.affiliation: Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China.
authors.forename: Shaofang
authors.initials: S
authors.lastname: Shangguan
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Shaoyan
authors.initials: S
authors.lastname: Chang
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Lu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Lihua
authors.initials: L
authors.lastname: Wu
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
authors.forename: Xiuwei
authors.initials: X
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Guan
authors.forename: Yihua
authors.initials: Y
authors.lastname: Bao
authors.forename: Huizhi
authors.initials: H
authors.lastname: Zhao
authors.forename: Jizhen
authors.initials: J
authors.lastname: Zou
authors.forename: Bo
authors.initials: B
authors.lastname: Niu
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
mesh_terms: D001483:Base Sequence; D001921:Brain / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D005333:Fetus / Q000378:metabolism / Q000473:pathology; D051157:Frizzled Receptors / Q000235:genetics*; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease; D005838:Genotype; D005865:Gestational Age; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009436:Neural Tube Defects / Q000150:complications / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011247:Pregnancy; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012307:Risk Factors; D016135:Spinal Dysraphism / Q000209:etiology* / Q000473:pathology
chemical_list: C105574:FZD3 protein, human; D051157:Frizzled Receptors
keywords: DNA methylation; FZD3 gene; planar cell polarity; single nucleotide polymorphism; spina bifida