While no prior study has delved into the physiological significance of serum calsarcin-2 concentration, our mouse study has illuminated a negative correlation between serum calsarcin-2 levels and an index of skeletal muscle mass (Figure 5A), as higher muscle calsarcin-2 expression was noted in HFD-induced sarcopenia mice (Figure 1C). The gene discussed is MYOZ1; the disease is sarcopenia.