The Elastin and Fibrillin2 genes and the risk of Achilles tendon pathology

Objective: Achilles tendon pathology (ATP) is a multifactorial condition for which genetic risk factors have been identified. Variants within the COL5A1, MMP3 and GDF-5 genes have been associated with this condition. The Elastin (ELN) proteins give elasticity to tendons, allowing them to stretch and return to their original state. The Fibrillin-2 (FBN2) glycoproteins play important roles in the formation of microfibril filaments, providing strength and flexibility to tendons. Mutations within the ELN and FBN2 genes have been linked to Marfan’s syndrome and contractual congenital arachnodactyly respectively. Furthermore, the ELN rs2071307 and the FBN2 rs331079 variants have been found to associate with aortic and intracranial aneurysm respectively; therefore disrupting the extracellular matrix. The aim of this study was to determine whether these polymorphisms were associated with the risk of ATP in two independent populations. Design and Method: 213 (115 ATP cases and 98 asymptomatic controls) South African Caucasian participants and 209 (60 ATP cases and 149 asymptomatic controls) Australian Caucasian participants were recruited for this case-control genetic association study. All participants were genotyped using TaqMan technology for the ELN G/A rs2071307 and FBN2 G/C rs331079 polymorphisms. Results: The genotype frequency of FBN2 rs331079 was significantly different (P=0.043) between the ATP (GG, 86.2%; GC, 13.2%; CC, 0.6%) and CON (GG, 76.9%; GC, 21.0%; CC, 2.1%) groups. There was no significant association between ELN rs2071307 (P=0.804) and risk of ATP. Conclusion: This study shows for the first time that variation within the FBN2 gene is associated with ATP in Caucasian cohorts.