GDF5 and osteoarthritis: Mutations in GDF5 are associated with various skeletal disorders such as brachydactyly, proximal symphalangism, acromesomelic dysplasia, multiple synostoses syndrome, chondrodysplasia, and susceptibility to osteoarthritis (Enochson, Stenberg, Brittberg, & Lindahl, 2014; Francis‐West et al., 1999; Polinkovsky et al., 1997; Ratnayake et al., 2017; Thomas et al., 1997, 1996).