Cases have been reported in which, after a preliminary diagnosis of MPS, as a result of genetic testing, it turned out that patients suffered from OI associated with mutations in collagen-coding genes (COL1A2), while no mutations in the lysosomal genes were identified (Mutlu et al. 2015; Hamatani et al. 2018). The gene discussed is COL1A2; the disease is osteogenesis imperfecta.