Table 2.

Mouse and Rat Models of Altered Bone Quality

Human Disease	Mouse Phenotype	Basis for Phenotype	Ref
Osteogenesis Imperfecta	Brittle bones altered mineralization	Several models with defects in type I collagen genes or genes for processing molecules, for example: MOV13: heterozygous null mutations in COL1A1 oim/oim: homozygous for a frameshift deletion in COL1A2, leading to a failure to integrate the protein into the procollagen trimer Brtl: targeted substitution of a glycine by cysteine in the triple helical domain Cartilage associated protein knockouts provide models of type VII OI	23
Osteopetrosis	High bone mass/altered osteoclast function	Knockouts of: c-SRC, cathepsin K, carbonic anhydrase II, CLCN7, Ostm1 Naturally occurring mutants: oc/oc and grey lethal mice, ia/ia rat	26
High bone mass	Increased bone mass	Knockouts of: Sclerostin, glycogen synthase kinase 3beta; secreted Frizzled-related protein 1; Dickkopf 1; myostatin	27
Low bone mass	Decreased bone formation	WNT-signaling protein knockouts; biglycan knockout	28
Osteoporosis	Decreased bone density	Fibromodulin/biglycan double knockout	14
Hypophosphatemic rickets	Poorly mineralized bone	Dentin matrix protein-1 knockout	13