Genetically modified mice add another line of evidence to the role of SOST in bone mineral density (BMD) determination: Sost-knock-out (KO) mice show high BMD and bone strength, with a high number of osteoblasts and increased bone formation that reproduce the phenotype observed in patients with sclerosteosis or Van Buchem’s disease [33,34]. This evidence concerns the gene SOST and hyperostosis corticalis generalisata.