MMP9 and skeletal dysplasia: Five novel pathogenic/likely pathogenic variants, including the c.151 C > T and c.929del in MMP9, c.3977T > G in COL1A1, c.3130_3131dup in TTC21B, and c.3850 C > T in COL11A2 were found in 4 cases with skeletal dysplasia.