Association of genetic and mechanical factors with age of onset of knee osteoarthritis / 中华医学遗传学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To analyze the relationship of genetic and mechanical factors with age of onset of knee osteoarthritis (OA).</p><p><b>METHODS</b>Cross-sectional and longitudinal studies were conducted in 863 patients with knee OA and 999 age-matched controls from Chinese Han population with complete clinical data. Single nucleotide polymorphisms of + 104T/C in rs143383 of the growth differentiation factor 5 (GDF5) gene and the aspartic acid repeat polymorphism of the asporin gene ASPN were genotyped by taqman probe and polyacrylamide gel electrophoresis respectively.</p><p><b>RESULTS</b>Body mass index (BMI) in subjects with knee OA was significantly higher than that in controls (P< 0.01). Obesity (BMI≥ 25) was a high risk factor for knee OA (P< 0.01). Regression analysis showed that there was a certain correlation between the BMI and age of onset of the knee OA (Pearson= 0.15, P< 0.01). To analyze the BMI distribution, the two groups were subgrouped by age with 5-year interval. The BMI in early-onset patients was lower than that in the late-onset patients (F= 2.497, P= 0.011). However, there was no significant difference in the control subgroups. Frequencies of the GDF5 and ASPN alleles distributed differently between the early- and late-onset patients (P< 0.05).</p><p><b>CONCLUSION</b>Genetic factors play an important role in knee osteoarthritis of early-onset patients, whereas mechanical factor play an important part in knee osteoarthritis of late-onset patients.</p>