It has been found that osteocyte-selective PTH/PTHrP receptors (PPR) knockout (Ocy-PPRcKO mice) revealed a reduction in trabecular bone and slight osteopenia correlated with the elevated expression of SOST, which, yet, were unable to be suppressed by PTH in the Ocy-PPRcKO animals128. The gene discussed is PTH; the disease is Osteopenia.