GDF5 and Hip dysplasia: Further genetic evidence for the involvement of joint shape in the development of OA comes from a recent genome-wide association study (GWAS) of 770 cases with DDH and 3364 healthy controls, in the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man (NJR), which identified rs143383 variant in GDF5 to be robustly associated with DDH case status [13]; the same variant has also been reported to be associated with increased risk of OA [14].