VHL and pachyonychia congenita: Several genes are involved in the pathogenesis of PC, such as the RET proto-oncogene, von Hippel–Lindau disease tumor suppressor (VHL), neurofibromatosis type 1 tumor suppressor (NF1), genes encoding the succinate dehydrogenase (SDH) complex subunits, TMEM127, and MYC-associated factor X (MAX) [4].