In 14 OI forms, mutations affecting collagen I chains (α1/2), collagen I associated chaperones (HSP47, SPARC, FKBP10), enzyme complexes involved in its post-translational modification (P3H1 complex, P4HB), proteins involved in its intracellular transfer from ER to Golgi (KDLR2, SEC24D), transcription factor regulating its expression (OASIS) or an ER channel involved in modulating calcium flux (TRIC-B) result in intracellular collagen retention. The gene discussed is SERPINH1; the disease is osteogenesis imperfecta.