Both Col2a1expDmm/Dmm mice harboring a mutation in the C-propeptide globular domain of type II collagen (Col2a1) (Pace et al., 1997) as well as mice containing an R992C mutation associated with spondyloepiphyseal dysplasia Arita et al., 2015 have defects in the assembly and folding of type II collagen, that alter collagen distribution/orientation (Arita et al., 2015; Brown et al., 1981; Pace et al., 1997). This evidence concerns the gene COL2A1 and spondyloepiphyseal dysplasia.