title: Human COL5A1 rs12722 gene polymorphism and tendon properties in vivo in an asymptomatic population.
abstract: OBJECTIVE
  Gene variants encoding for proteins involved in homeostatic processes within tendons may influence its material and mechanical properties in humans. The purpose of this study was to examine the association between one such gene variant, gene encoding collagen type V alpha 1 chain (COL5A1) rs12722, and patellar tendon dimensions and mechanical properties in vivo.
  
  
  METHODS
  Eighty-four recreationally active, Caucasian, men and women, aged 18-39, with no history of injuries to the knee and a body mass index between 18.5 and 30 were recruited. Women were not recruited if they were pregnant or using any form of hormone-based contraception. The COL5A1 rs12722 genotype was determined using real-time polymerase chain reaction. Patellar tendon dimensions (volume) and functional (elastic modulus) properties were assessed in vivo using geometric modelling, isokinetic dynamometry, electromyography and ultrasonography.
  
  
  RESULTS
  After adjustments for non-genetic factors, no significant associations were evident between the COL5A1 rs12722 gene variant and either patellar tendon volume (P = 0.933) or elastic modulus (P = 0.206), nor with a calculated Z score that combined these dimensional and functional properties into a composite value (P = 0.647). Similarly, no association was evident when comparing individuals with/without the rare C allele (volume, P = 0.883; elastic modulus, P = 0.129; Z score, P = 0.631).
  
  
  CONCLUSIONS
  Tendon properties do not seem to be influenced by the COL5A1 rs12722 gene variant. Although the COL5A1 rs12722 polymorphism has previously been associated with the risk of tendon pathology, that association is unlikely to be mediated via underlying tendon dimensional and functional properties.
authors.affiliation: Maternal and Fetal Health Research Group, Institute of Human Development, St. Mary's Hospital, University of Manchester, 5th Floor, Oxford Road, Manchester, M13 9WL, UK, brandon.foster-2@manchester.ac.uk.
authors.forename: Brandon Paul
authors.initials: BP
authors.lastname: Foster
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Morse
authors.forename: Gladys L
authors.initials: GL
authors.lastname: Onambele
authors.forename: Alun G
authors.initials: AG
authors.lastname: Williams
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D024062:Collagen Type V / Q000235:genetics*; D055119:Elastic Modulus; D004576:Electromyography; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000502:physiology; D017847:Patellar Ligament / Q000000981:diagnostic imaging / Q000502:physiology*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D014463:Ultrasonography; D055815:Young Adult
chemical_list: C530725:COL5A1 protein, human; D024062:Collagen Type V