Terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling (TUNEL) assay showed no difference in osteocyte apoptosis in both controls and Dmp1-PPRKO mice, both in males and females (Supplementary Figure 2C, 2D), suggesting that mechanisms other than osteocyte apoptosis are responsible for the osteopenia. This evidence concerns the gene DMP1 and Osteopenia.