Indeed, our finding that DNMT1 is overexpressed in the trabecular bone of patients and mice with SOP and our previous finding that DNMT1 expression is upregulated in the femoral tissues of rats with disuse osteoporosis (Li et al., 2018) together support the crucial role of DNMT1 in suppression of bone formation in vivo. The gene discussed is DNMT1; the disease is osteoporosis.