COL2A1 and spondyloepimetaphyseal dysplasia: COL2A1 c.3121G > A (p.G1041S) has been reported to be a pathological mutation clinically associated with spondyloepimetaphyseal dysplasia (SEMD) that was also noted in P7 (Supplementary Figure 2E; Meredith et al., 2007; Zhang et al., 2015).