We found that TYMS rs2606241 (P = 0.022), TYMS rs2853741 (P = 0.019), MTHFR rs3737964 (P = 0.029), and MTHFR rs4846048 (P = 0.030) were associated with the risk of HFS (Table 3). Here, MTHFR is linked to Hand-foot syndrome.