Investigation of Variants within the COL27A1 and TNC Genes and Achilles Tendinopathy in Two Populations
Saunders CJ., van der Merwe L., Posthumus M., Cook J., Handley CJ., Collins M., September AV. Journal of Orthopaedic Research Month. 2012;
The risk of developing Achilles tendinopathy is strongly related to intrinsic factors such as an individual’s genes (genotype). Previous research has found that 2 genes, which encode proteins in the composition of tissue, may be associated to Achilles tendinopathy (COL5A1 and TNC). COL27A1 is another gene in close in proximity to both of those genes and provides instructions for a type of collagen. Therefore, the purpose of this study was to view the association between the risk of Achilles tendinopathy and several genetic variants (specifically, single nucleotide polymorphisms;SNPs), including COL27A1 and TNC genes. The authors explored these associations in two populations. The first population consisted of 131 South African asymptomatic control participants and 94 South African participants with diagnosed Achilles tendinopathy. The second population was 208 Australian asymptomatic control participants and 85 Australian participants diagnosed with Achilles tendinopathy. The authors evaluated (genotypedfour SNPs (rs4143245, rs1249744, rs753085, rs946053) within COL27A1 and 3 SNPs (rs13321, rs 2104772, rs1330363) within TNC. The South African and Australian populations had similar genotypes so the data from both cohorts were combined for further analysis. After that, the authors found the presence of two SNPs in the TNC gene were different between participants diagnosed with Achilles tendinopathy compared to the controls (rs2104772 and rs1330363). Specifically, athletes that carry one variation within the TNC SNP rs2104772 (an A instead of the T allele) may be almost 10 times more likely to sustain an Achilles tendinopathy than those carrying the T allele. This variant may change the amount of protein that is produced that is responsible for tissue healing. Conversely, those carrying one variation within the TNC SNP rs1330363 (G instead of the C allele) were found to be 15 times less likely to develop Achilles tendinopathy compared to those carrying the C allele. Furthermore, the inheritance of a cluster of SNPs (haplotype; rs946053-rs13321-rs2104772) occurred more frequently in those diagnosed with Achilles tendinopathy compared to controls. The authors found no other differences between those with and without Achilles tendinopathy.
This study helps to establish genetic factors that could increase the risk of Achilles tendinopathy. These variations may influence how much protein is made as well as the quality of the protein being produced. Due to the differences in the proteins these variations could also lead to changes in how the proteins interact with one another as well as protein-environmental interactions. These changes could also compromise the wound healing and remodeling. This study further implicates a specific region of the genome as contributing factor to one’s risk for Achilles tendinopathy. If we can understand the functional implications of these genetic variations we may be able to identify mechanisms of disease and patients at increased risk for Achilles tendinopathy. This knowledge could also help us develop individual programs for prevention and rehabilitation. This study is a good example of genetic research being conducted in areas related to sports medicine. Do you feel that genotyping may play an important role in prevention and treatment of injuries?
Written by: Jane McDevitt, MS, ATC, CSCS
Reviewed: Jeffrey Driban
Saunders CJ, van der Merwe L, Posthumus M, Cook J, Handley CJ, Collins M, & September AV (2012). Investigation of variants within the COL27A1 and TNC genes and Achilles tendinopathy in two populations. Journal of Orthopaedic Research PMID: 23192621