title: Duplication of MER115 on chromosome 4 in patients with primary biliary cirrhosis.
abstract: BACKGROUND
  Primary biliary cirrhosis (PBC) is a complex disease with genetic and environmental influences. The disease is more prevalent in families with PBC and candidate gene case-control studies have linked PBC with DRB1(*)08 human leucocyte antigen class II alleles.
  
  
  OBJECTIVE
  The goal of this study was to characterize a MER115 intergenic region on chromosome 4 as a putative genetic variant associated with PBC.
  
  
  RESULTS
  This region was incidentally identified during investigations to discover candidate microbial agents using representational difference analysis (RDA) with liver samples from patients with PBC and primary sclerosing cholangitis (PSC). blast search analysis of all the RDA products from the PBC liver revealed genomic sequences, whereas Escherichia coli, mycoplasma and hepatitis B virus DNA were found in the PSC liver. We identified one of the PBC RDA products as an ancestral repeat, referred to as MER115. Southern blot analysis with the PBC product uncovered a restriction fragment length polymorphism in PBC patients' liver. Southern blot hybridization signal showed increased signal intensity in PBC vs. control patients' DNA (P<0.005) and slot blot hybridization studies confirmed a copy number variation of the MER115 in hepatic DNA of PBC vs. control patients (P=0.02).
  
  
  CONCLUSIONS
  Further comparative genetic studies will be required to determine the extent of genomic duplication associated with MER115 and provide data on the possible copy number variants of genes close to this intergenic region in patients with PBC.
authors.affiliation: PVSS, FADDL, APHIS, USDA, Greenport, NY, USA.
authors.forename: Lizhe
authors.initials: L
authors.lastname: Xu
authors.forename: Linsheng
authors.initials: L
authors.lastname: Guo
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Shen
authors.forename: George
authors.initials: G
authors.lastname: Loss
authors.forename: Robert
authors.initials: R
authors.lastname: Gish
authors.forename: Shawn
authors.initials: S
authors.lastname: Wasilenko
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Mason
mesh_terms: D015139:Blotting, Southern; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D042622:DNA Repeat Expansion / Q000235:genetics*; D021901:DNA, Intergenic / Q000235:genetics*; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric
chemical_list: D017931:DNA Primers; D021901:DNA, Intergenic