Sports Medicine Research: In the Lab & In the Field: The Role of Genetics in Achilles Tendon Pathology (Sports Med Res)


Monday, May 6, 2013

The Role of Genetics in Achilles Tendon Pathology

Polymorphic Variation within the ADAMTS2, ADAMTS14, ADAMTS5, ADAM12, and TIMP2 Genes and the Risk of Achilles Tendon Pathology: A Genetic Association Study

El Khoury L, Posthumus M, Collins M, Handley CJ, Cook J, Raleigh SM. J Sci Med Sport. 2013 Mar 11

Take Home Message: Achilles tendon pathology is associated with variation within a gene (TIMP2) responsible for inhibiting enzymes responsible for collagen degradation. Genetic pre-screening of at-risk individuals may help guide individualized treatment strategies.

Genetic risk factors have recently been identified for Achilles tendon pathology, which may allow for genetic screening and identification of at-risk patients and could help guide clinical management of this injury. Specifically, previous studies reviewed by SMR have shown that variants within genes that encode for structural and regulatory proteins (such as Col5a1 and TNC) are associated with risk of Achilles tendon pathology.  However, additional genes encoding for enzymes that breakdown the extracellular matrix and their inhibitors (such as the ADAM, ADAMTS, and TIMP family of proteins) have not yet been evaluated.  Therefore, the purpose of this study was to determine if variations within these genes are associated with Achilles tendon pathology.  The authors recruited 178 Caucasian participants diagnosed with Achilles tendon pathology (59 Australian and 114 South African, 134 chronic and 39 acute ruptures) and 248 asymptomatic Caucasian controls (152 Australian and 96 South African). DNA was extracted from whole blood and all participants were genotyped for gene variants.  A significant association was found between a TIMP2 variant and Achilles tendon pathology.  Additionally, a significant interaction between an ADAMTS14 variant and age of onset of Achilles tendon pathology was also identified. 

This study introduces a TIMP2 variant as a significant risk factor for Achilles tendon pathology.  TIMP2 is an inhibitor of matrix metalloproteinases, which are enzymes responsible for extracellular matrix degradation.  Increases in TIMP2 levels may disrupt extracellular matrix remodeling and overall tendon health.  The authors also identified a variant within the ADAMTS14 gene that appeared to delay the onset of Achilles tendon pathology in those affected.  ADAMTS14 is responsible for cleavage of pro-collagen – an event which precedes the production of collagen.  Results from this study suggest a protective role may exist for this ADAMTS14 genotype.  Recently, much attention has been placed on identifying genetic variations and understanding their association with tendon pathology.  This study and previous studies have concluded that genetic risk factors likely exist in tendon pathology. Therefore, prescreening of individuals for these genetic variants may help with clinical management.  Specifically, individuals identified as genetically at risk may benefit from individualized rehabilitation programs and more conservative return to sport criteria. Despite these findings, Achilles tendon injury is likely due to a complex interaction between both intrinsic (e.g., genetic) and extrinsic (e.g., repetitive mechanical stress) factors and therefore all factors should be considered when treating patients.  

Do you think that individualized rehabilitation protocols could improve outcomes in at risk patients?  Do you think genetic testing should be implemented in college or professional sports? 

Written by: Katherine Reuther
Reviewed by:  Stephen Thomas

Related Posts: 

El Khoury L, Posthumus M, Collins M, Handley CJ, Cook J, & Raleigh SM (2013). Polymorphic variation within the ADAMTS2, ADAMTS14, ADAMTS5, ADAM12 and TIMP2 genes and the risk of Achilles tendon pathology: A genetic association study. Journal of Science and Medicine in Sport PMID: 23491141


Aja Corchado said...

As the article stated, this study could help athletic trainers and other medical personnel better treat athletes that have Achilles tendon pathology. My question is what could athletic trainers do to help prevent athletes who have the genetics that could predispose them to Achilles tendon pathology from becoming injured? Are there specific treatments to help reduce the possibility of an athlete being diagnosed or is it something that can not be avoided and instead this article is meant mostly for the treatment of the injury after it happens?

Katie Reuther said...

Thanks for your comment. This article suggests that certain individuals may be genetically pre-disposed to Achilles Tendon pathology. It is also possible that these individuals are more sensitive to extrinsic factors that lead to tendon pathology. With this information, athletic trainers could possibly identify at-risk individuals and develop more individualized treatment strategies. Some examples include limiting excessive loading and overuse of the tendon to prevent permanent damage and implementing conservative treatment strategies when managing the injury.

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