title: An exon polymorphism of programmed cell death 1 gene is associated with both the susceptibility and thoracolumbar kyphosis severity of ankylosing spondylitis in a Chinese Han population.
abstract: BACKGROUND
  Although human leukocyte antigen (HLA)-B27 gene is the major susceptible gene associated with ankylosing spondylitis (AS), it has been recognized that non-HLA-B27 genes also play key roles in the development of AS. The purpose of this study is to investigate whether a single nucleotide polymorphism (SNP) in the exon region of the programmed cell death 1 (PDCD-1) gene is associated with the susceptibility or the thoracolumbar kyphosis severity of AS in a Chinese Han population.
  
  
  METHODS
  A total of 255 AS patients between January 2008 and October 2012 were recruited in this study. Two hundred and three healthy patients were recruited as normal controls. According to the severity of thoracolumbar kyphosis, the AS patients were further divided into group A (patients with kyphosis <70°, n = 135) and group B (patients with kyphosis ≥70°, n = 120). One exon polymorphism, rs2227982 (C/T) of PDCD-1 gene, was selected for analysis. Genotyping was performed by TaqMan probe assays in all the subjects.
  
  
  RESULTS
  There were significant differences of genotype distributions of rs2227982 between AS patients and normal controls. The frequency of the T allele was significantly higher in AS patients when compared with normal controls. The frequency of the T allele in group B was significantly higher than that in group A. Carriage of the TT genotype increased the risk of severe thoracolumbar kyphosis 1.9-fold in AS patients.
  
  
  CONCLUSIONS
  Our study confirms a significant association between the SNP rs2227982 of PDCD-1 gene and the susceptibility of AS in a Chinese Han population. Moreover, the TT genotype is suggested to be associated with the severity of thoracolumbar kyphosis secondary to AS.
authors.affiliation: Department of Spine Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road 321, Nanjing 210008, China.
authors.forename: Bang-ping
authors.initials: BP
authors.lastname: Qian
authors.forename: Xin-qiang
authors.initials: XQ
authors.lastname: Wang
authors.forename: Yong
authors.initials: Y
authors.lastname: Qiu
authors.forename: Hua
authors.initials: H
authors.lastname: Jiang
authors.forename: Ming-liang
authors.initials: ML
authors.lastname: Ji
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics; D005091:Exons / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007738:Kyphosis / Q000209:etiology / Q000235:genetics*; D008159:Lumbar Vertebrae / Q000002:abnormalities*; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D061026:Programmed Cell Death 1 Receptor / Q000235:genetics*; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000235:genetics*; D013904:Thoracic Vertebrae / Q000002:abnormalities*; D055815:Young Adult
chemical_list: D061026:Programmed Cell Death 1 Receptor