CDC73 and pachyonychia congenita: The strengths of our study are that: i) it includes a large series of patients with PC whose histological diagnosis has been established according to the latest WHO guidelines; ii) the median follow-up after PTx was reasonably long; iii) the CDC73 mutational analysis and parafibromin studies were performed in a single center, thus avoiding potential problems originating from the use of different techniques and immunohistochemical scoring systems.