title: Association study between growth differentiation factor 5 polymorphism and non-contact anterior cruciate ligament rupture in Chinese Han population.
abstract: BACKGROUND
  Anterior cruciate ligament (ACL) rupture is the most common ligamentous injury for active adolescents and young adults each year. However, the precise etiologies of ACL injury are not fully understood. The present study was to investigate +104T/C polymorphism of growth differentiation factor 5 (GDF5) gene in patients with ACL rupture, and evaluate the effects of polymorphism on GDF5 mRNA levels in ligament of patients with ACL rupture in central China.
  
  
  METHODS
  A total of 286 Chinese patients with ACL rupture and 500healthy controls were enrolled in this study. The +104T/C polymorphism in GDF5 gene were genotyped by DNA sequencing. GDF5 mRNA expressions levels in ligament were determined by quantitative PCR.
  
  
  RESULTS
  The frequency of the TT genotype tended to be higher in ACL rupture group than in control group (62.6% vs. 48.0%, P< 0.001, OR = 1.81, 95% CI: 1.35-2.44). T allele of the GDF5 +104T/C polymorphism was more common in ACL rupture group than in control group (P< 0.001). Patients carrying TT genotype expressed lower levels of GDF5 mRNA than C carriers (P = 0.005) among ACL rupture.
  
  
  CONCLUSIONS
  Our study indicated that GDF5 +104T/C polymorphism was associated with ACL rupture patients in central China. This is likely from decreased expressions of GDF5 mRNA. Further studies are necessary to explore the functional implication of the GDF5 +104T/C polymorphism in Chinese ACL rupture patients.
authors.affiliation: Department of Orthopaedic Surgery, Zhongnan Hospital, Wuhan University Wuhan, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Chen
authors.affiliation: Department of Orthopaedic Surgery, Zhongnan Hospital, Wuhan University Wuhan, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Orthopaedic Surgery, Zhongnan Hospital, Wuhan University Wuhan, China.
authors.forename: Yong-Jian
authors.initials: YJ
authors.lastname: Qi
authors.affiliation: Department of Orthopaedic Surgery, Zhongnan Hospital, Wuhan University Wuhan, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Tie
authors.affiliation: Department of Orthopaedic Surgery, Zhongnan Hospital, Wuhan University Wuhan, China.
authors.forename: Liao-Bin
authors.initials: LB
authors.lastname: Chen
keywords: Anterior cruciate ligament; expression; growth differentiation factor 5; polymorphism; rupture