CHST3 and osteogenesis imperfecta: Furthermore, in MBTPS2-OI fibroblasts we identified changes in the expression of genes involved in bone and cartilage development, namely CHST3 and PAPSS2 that are regulated by OASIS, and VEGFA, ADAMTS12 and DKK1. These in vitro findings generate new insights and open up new hypotheses on mechanisms that could contribute to and/or counter act the disease progression in OI.