This study connects skin aging with age-related bone loss and confirms that improving the level of Cystatin-A in the skin could serve as a potential topical treatment for age-related OP.210 The same research group also generated a single-cell nuclear transcriptome atlas of skeletal muscle, revealing the critical role of FOXO3 in counteracting skeletal muscle aging.211 These findings provide a theoretical basis for further development of diagnostic and intervention strategies for skeletal muscle aging. The gene discussed is CSTA; the disease is aging.