P4HA2 and osteogenesis imperfecta: Similarly, the p3h1, whose human ortholog is involved in osteogenesis imperfecta [50] and p3h3 genes code for prolyl-3-hydroxylases, while the p4ha1a and the p4ha2 genes code for prolyl-4-hydroxylases whose mutation in mouse causes impaired ECM, chondrodysplasia, and kyphosis [51].