Inpatients with mutations in the MBTPS2 gene, lysine hydroxylationof the α1 (I) chain and α2 (I) chain is reduced, collagencrosslinking is altered, and bone tissue strength is impaired.One of the transcription factors activated by RIP is a specificastrocyte-induced substance (OASIS; encoded by CREB3L1).A deficiency of this substance has been reported in associationwith a family with severe osteogenesis imperfecta. Here, MBTPS2 is linked to osteogenesis imperfecta.