Because both trabecular and cortical bone mass were increased by the Lrp5A213V/A213V genotype to a similar extent in wild-type and Wnt1G177C/G177C mice and because we did not observe skeletal fractures in 24-week-old Wnt1G177C/G177C; Lrp5A213V/+ or Wnt1G177C/G177C; Lrp5A213V/A/213V mice, it is reasonable to speculate that antibodies neutralizing sclerostin can mediate a beneficial osteoanabolic effect in OI-XV patients, especially when taken into consideration that these will interfere not only with the binding of sclerostin to LRP5 but also with LRP6. This evidence concerns the gene LRP5 and osteogenesis imperfecta.