PAPPA2 and Hip dysplasia: Despite the fact that gene variants such as ESR1, Hoxb9, IL6, PAPPA2, UQCC, and VDR were associated with DDH, other case-control studies did not report a significant difference (Granchi et al., 2002; Kapoor et al., 2007; Rouault et al., 2009; Yamanaka et al., 2009; Kolundzic et al., 2011; Jia et al., 2012; Christians et al., 2013; Hao et al., 2014; Jawadi et al., 2018; Feldman et al., 2019; Harsanyi et al., 2021b; Gumus et al., 2021).