Scientist identify genetic polymorphisms associated with rapid progression of knee osteoarthritis

Paris, June 12, 2014. A multi center, four-year long clinical study involving 282 primary knee OA patients, 31 Spanish healthcare centers and professionals from different fields, has identified the genetic polymorphisms or SNPs (Single Nucleotide Polymorphisms) significantly associated with rapidly evolving knee osteoarthritis. There are eight hereditary genetic variants associated with severe knee osteoarthritis. The genetic component of osteoarthritis is very important, for it influences both its development as well as its progression. There are epidemiologic studies that estimate that knee OA is hereditary in 40% of cases and that the progression is hereditary in 60-70% of cases, affirmed Dr. Ingrid Möller, director of the Poal institute of Rheumatology of Barcelona and one of the authors of this study. These new findings were presented at the European Congress of Rheumatology being held in Paris.

Patients were classified into two groups: poor prognosis cases and those having slow progression, i.e. good prognosis cases. There were analyzed 774 SNPs, evaluating clinical variants as potential predictors. Later, they developed a predictive mathematical model which was clinically validated in a second cohort of primary knee OA patients.

The model thus developed combines the information of a clinical variant (age at the moment of diagnosis) and 8 SNPs (rs2073508, rs10845493, rs2206593, rs10519263, rs874692, rs7342880, rs780094 and rs12009). SNPs contribute 78% of the predictive capacity of the Arthrotest® model, the remaining 22% being the age at the time of the diagnosis of OA. SNP rs2073508 from the TGFB1 gene (involved in the metabolism of glucose) are the SNPs contributing the most to the predictive value of the model.

Furthermore, it is the first time that a direct relationship between the GCKR2 gene and OA or its progression has been found. This gene, previously related to an elevated risk of type 2 diabetes, can be found as one of the eight SNPs of the Arthrotest® model, rs780094. The identification of these genetic polymorphisms has allowed the development of a diagnostic tool to predict progression of primary knee OA- Arthrotest®. It is the world’s first genetic saliva test that can predict genetic predisposition to rapidly progressing severe knee OA. This test allows physicians to identify rapid progression, poor prognosis cases which have, therefore, an elevated risk of needing prosthetic surgery in the short term. “For a disease such as OA, which very often has been considered a minor ailment, this is an important step forward-it raises awareness about this disease, allowing us to act during its early stages, optimizing resources and disease control”, affirmed Dr. Möller. This product has been commercially available for one year. Since it is still patent pending, until now it has not been possible to report the study’s specific results.