Cindy Boer

272 | Chapter 6 have been reported. Although, these only explain 6-21% of the genetic heritably for os- teoarthritis, they may explain sufficient genetic risk to be successfully used in a PRS, for example hip osteoarthritis where 21% of the genetic heritability is explained. We might be able to identify individuals at high risk of developing hip osteoarthritis, preferably at an early age before osteoarthritis onset, and take preventative measures[60]. These would include the prevention of environmental osteoarthritis risk factors, such as obe- sity. No treatment strategies exist (for now) for osteoarthritis, thus such preventative measure could be extremely valuable, especially in individuals with a high genetic risk of osteoarthritis. By lowering environmental risk factors such individuals could either prevent osteoarthritis or extend the age of onset of osteoarthritis. In addition, PRS could also be used in osteoarthritis patients to identify which underlying pathological pathway are driving their osteoarthritis. Using the translation- al knowledge of , i.e., of which genes and pathways, of the SNVs included in the PRS, the pathological pathways involved can be identified. Allowing for a “personalized medi- cine” approach for identifying subgroups of osteoarthritis patients and adjusting ther- apeutic strategies accordingly Here, it becomes evident why GWAS needs to be done on globally diverse populations. If we do not take into consideration differences between populations, the possibility exists that the developed PRS is only effective in one specific population. Possibly of widening existing disparities and excluding minority popula- tions of valuable osteoarthritis clinical care. Although seemingly much needs to be done to move from “bench to bedside”, the current SNV array prices have reached a record low (~€30,- per sample). Combined with the rapid increase in understanding of osteoarthritis genetics, clinical implications might reach the “bedside” soon. Hopefully the research presented here and suggestions for future research will contribute to help lower the burden of osteoarthritis, which has been plaguing synovial joints for hundreds of millions years.