CHSY1 and pachyonychia congenita: Consistent with the result of TWAS, previous studies have reported 4 of the 19 genes (PPP2R2A, E2F3, KCNK5, and SOX4) play important roles in the development of PC,20, 21, 22, 23 and 2 of the 19 genes (CHSY1 and EGLN3) have been proved associated with PC via bioinformatics methods.25, 26 SOX4 is significantly associated with PC and overexpressed in PC patients.