Although we could not find any methylation studies about the evaluation of GDF5 in the field of DDH disease, but previous studies showed that GDF5 promoter in osteoarthritis (OA) patients is regulated by methylation (Reynard, Bui, Canty‐Laird, Young, & Loughlin, 2011; Reynard, Bui, Syddall, & Loughlin, 2014). Here, GDF5 is linked to osteoarthritis.