MMP-1 promoter genotype and haplotype association with posterior tibial tendinopathy

• MMP-1 haplotypes are associated with the posterior tibial tendinopathy.
• Haplotypes MMP-1 had significant risk effect on tibial tendon insufficiency.
• Polymorphisms in MMP-1 isolated and haplotype are associated to tendinopathy.
• The influence of genetic polymorphisms in tendinopathy.
• Polymorphisms influence the tendinopathy process through the effect of multiple SNP.

PurposePosterior tibial tendon (PTT) is particularly vulnerable and its insufficiency is recognized as the main cause of adult acquired flatfoot. Some patients have a predisposition without clinically recognized cause, suggesting that individual characteristics play an important role in tendinopathy. The objective of the present study is to investigate the association of − 519 (rs1144393) matrix metalloproteinase-1 (MMP-1) polymorphism and the − 1607 (rs1799750) and − 519 MMP-1 haplotypes and risk of PTT dysfunction.MethodsThe test group included 50 females who presented PTT dysfunction Grade 2 or 3, and who were submitted to surgical treatment, with histopathological examination of the tendon and magnetic resonance image (MRI) confirming tendinopathy, while the control group was 100 asymptomatic women who present intact PTT at MRI. We analyzed functional polymorphisms MMP-1 and their haplotypes using polymerase chain reaction and restriction fragment length analysis.ResultsThere was a significant difference in the presence of the different alleles and genotypes between the control group and test group for the MMP-1 gene (p ≤ 0.01). The G allele of the − 519 MMP-1 polymorphism increased susceptibility to degeneration in the PTT tendon and seems to be a genetic risk factor. Global haplotype analysis indicated a significant difference between both groups (p < 0.0001). Haplotypes G–2G and A–2G had statistically significant risk effect on PTT insufficiency. G–2G, p < 0.001; OR = 5.72 (CI, 2.84–11.52) and A–2G p = 0.002, OR = 3.95 (CI, 1.65–9.44).ConclusionAccording to our results, − 519 MMP-1 isolated and − 1607/− 519 MMP-1 haplotypes are associated to tendinopathy in posterior tibial tendon.