Bone Abstracts

Classical osteogenesis imperfecta (OI) is caused by mutations in the two genes encoding type I collagen. OI is associated with low bone mass and abnormally high bone matrix mineralization. The Brtl/+ OI mouse is a knock-in model caused by a glycine substitution in one COL1A1 allele. Brtl/+ pups display 30% perinatal lethality; survivors have small size and brittle bone. Unexpectedly, homozygous Brtl/Brtl pups, producing only mutant collagen, have normal survival rates...

Mutations in the C-propeptide cleavage site of both COL1A1 and COL1A2 cause dominant high bone mass (HBM) osteogenesis imperfecta (OI), characterized by bone hypermineralization. To elucidate the role of C-propeptide processing in bone formation, we generated heterozygous HBM mice in which both residues of the COL1A1 cleavage site were mutated to prevent cleavage by BMP1. HBM mice are smaller than WT in both weight and length and have extremely brittle bones....