Interactions between collagen gene variants and risk of anterior cruciate ligament rupture.

The COL5A1 and COL12A1 variants are independently associated with modulating the risk of anterior cruciate ligament (ACL) rupture in females. The objective of this study was to further investigate if COL3A1 and COL6A1 variants independently, as well as, collagen gene-gene interactions, modulate ACL rupture risk. Three hundred and thirty-three South African (SA, n = 242) and Polish (PL, n = 91) participants with diagnosed ACL ruptures and 378 controls (235 SA and 143 PL) were recruited. Participants were genotyped for COL3A1 rs1800255 G/A, COL5A1 rs12722 (T/C), COL6A1 rs35796750 (T/C) and COL12A1 rs970547 (A/G). No significant associations were identified between COL6A1 rs35796750 and COL3A1 rs1800255 genotypes and risk of ACL rupture in the SA cohort. The COL3A1 AA genotype was, however, significantly (p = 0.036) over-represented in the PL ACL group (9.9%, n = 9) when compared to the PL control (CON) group (2.8%, n = 4). Although there were genotype distribution differences between the SA and PL cohorts, the T+A-inferred pseudo-haplotype constructed from COL5A1 and COL12A1 was significantly over-represented in the female ACL group when compared to the female CON group within the SA (T+A ACL 50.5%, T+A CON 38.1%, p = 0.022), PL (T+A ACL 56.3%, T+A CON 36.3%, p = 0.029) and combined (T+A ACL 51.8%, T+A CON 37.5%, p = 0.004) cohorts. In conclusion, the novel main finding of this study was a significant interaction between the COL5A1 rs12722 T/C and COL12A1 rs970547 A/G variants and risk of ACL injury. These results highlight the importance of investigating gene-gene interactions in the aetiology of ACL ruptures in multiple independent cohorts.

The association between the COL12A1 gene and anterior cruciate ligament ruptures.

BACKGROUND: Anterior cruciate ligament (ACL) ruptures are among the most severe musculoskeletal soft tissue injuries. However, the exact mechanisms which cause these acute injuries are unknown. Recently, sequence variants within two genes, namely COL1A1 and COL5A1, which code for the α1 chains of types I and V collagen respectively, were shown to be associated with ACL ruptures. Type XII collagen, similarly to types I and V collagen, is a structural component of the ligament fibril and is encoded by a single gene, COL12A1. OBJECTIVE: The aim of this study was to investigate whether sequence variants within COL12A1 are associated with ACL ruptures. METHODS: One hundred and twenty-nine (38 female) participants with clinically and surgically diagnosed ACL ruptures, as well as 216 (83 female) physically active controls participants (CON) without any history of ACL injury were included in this case-control genetic association study. All participants were genotyped for the AluI and BsrI restriction fragment length polymorphisms (RFLPs) within COL12A1. RESULTS: The AA genotype of the COL12A1 AluI RFLP was significantly over-represented in the female (OR=2.4, 95% CI 1.0 to 5.5, p=0.048), but not male (p=0.359) ACL participants. There were no genotype differences between the ACL and CON group for the BsrI RFLP. CONCLUSION: The COL12A1 AluI RFLP is associated with ACL ruptures among female participants in this study. The results suggest that females with an AA genotype are at increased risk of ACL ruptures. These initial genetic association studies should be explored further and, if repeated, incorporated into multifactorial models developed to identify predisposed individuals.

The COL5A1 gene is associated with increased risk of anterior cruciate ligament ruptures in female participants.

BACKGROUND: Anterior cruciate ligament ruptures, especially to young female athletes, are a cause of major concern in the sports medicine fraternity. The major structural constituents of ligaments are collagens, specifically types I and V. Recently, the gene that encodes for the alpha1 chain of type I collagen (COL1A1) has been shown to be associated with an increased risk of cruciate ligament ruptures. The COL5A1 gene, which encodes for the alpha1 chain of type V collagen, has been shown to be associated with Achilles tendon injuries. PURPOSE: The study was conducted to determine (1) if 2 sequence variants (BstUI and DpnII restriction fragment length polymorphisms [RFLPs]) within the COL5A1 gene are associated with an increased risk of anterior cruciate ligament ruptures, and (2) if there were any gender-specific positive associations between the 2 COL5A1 sequence variants and risk of anterior cruciate ligament ruptures. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: A total of 129 white participants (38 women) with surgically diagnosed anterior cruciate ligament ruptures and 216 physically active control participants (84 women) without any history of ACL injury were included in this case-control genetic association study. All participants were genotyped for the COL5A1 BstUI and DpnII RFLPs. RESULTS: There was a significant difference in the BstUI RFLP genotype frequency between the anterior cruciate ligament rupture and physically active control groups among the female participants, but not the male participants. The CC genotype in the female participants was significantly underrepresented in the anterior cruciate ligament rupture group compared with the controls (27.4% vs 5.6%; odds ratio = 6.6; 95% confidence interval, 1.5-29.7; P = .006). There were no differences in the DpnII RFLP genotype distributions between the anterior cruciate ligament rupture and physically active control groups. CONCLUSION: The CC genotype of the COL5A1 BstUI RFLP was underrepresented in female participants with anterior cruciate ligament ruptures. CLINICAL RELEVANCE: This is the first study to show that there is a specific genetic risk factor associated with risk of anterior cruciate ligament ruptures in female athletes.