Notably, the positive correlation between serum FGF21 levels and TACS in HD patients was also obtained in our study, which was contrary to the result that FGF21 inhibited vascular calcification in vitro and animal experiments [32,33], highlighting the need for further studies to explore the exact mechanism of FGF21 elevation on vascular calcification in CKD patients. This evidence concerns the gene FGF21 and Huntington disease.