NFATC1 and Osteopenia: The results regarding the role of NFAT signaling in osteoblasts, on the other hand, are more consistent, i.e., genetic inactivation of NFATc1 and NFATc2 in osteoblasts impairs osteoblastogenesis leading to osteopenia, whereas an opposite phenotype is observed when NFATc1 is specifically activated in the osteoblastic lineage (Koga et al., 2005; Winslow et al., 2006).