Sost (sclerostin) is a Wnt antagonist and osteocyte-expressed negative regulator of bone formation. Mutations in SOST are associated with an autosomal-recessive disorder, sclerosteosis, which causes progressive bone overgrowth. SOSTwt transgenic mice express human SOST in the mineralized bone of neonatal and adult mice (skull, rib, and femur) and in the adult heart and kidney. On the FVB/N background homozygous SOSTwt mice have fused and missing digits in both forelimbs and hindlimbs, decreased bone formation, decreased bone mineral density, decreased bone volume, trabecular number and thickness in the appendicular and axial skeleton. On the C57BL/6 background, SOSTwt mice exhibit fused and missing digits in both forelimbs and hindlimbs. Homozygous mice are viable and fertile, however, the donating investigator recommends breeding hemizygotes to wildtype (non-carrier) to avoid increasing foot/digit abnormalities. This strain may be useful for studying the physiologic role of SOST and as a model for drug development and mechanism validation.

SOSTwt transgenic mice express human SOST (sclerostin), a negative regulator of bone formation. Homozygous mice develop decreased bone mineral density and fused and missing digits in the forelimbs and hindlimbs. This strain may be useful for studying the physiologic role of SOST and as a model for drug development and mechanism validation.&nbsp;