Compound heterozygosity for a frameshift mutation and an upstream deletion that reduces expression ofSERPINH1in siblings with a moderate form of osteogenesis imperfecta

SERPINH1 encodes the collagen chaperone HSP47 that binds to arginine‐rich sequences in the type I procollagen trimers and provides the final steps in the folding and stabilization of the triple helical domain. Loss of both alleles in mice results in very early embryonic lethality. SERPINH1 mutations have been associated with one of the rarest forms of recessively inherited osteogenesis imperfecta (OI) with a moderate to severe phenotype. We...