HDAC4 and pachyonychia congenita: It is also notable that two histone deacetylase (HDAC4, HDAC10), the suppressor of EGR molecules NAB2, and SMAD3 are also down-regulated; the suppression of this latter molecule has been previously demonstrated at both the transcriptomic and epigenomic levels in the transition of human BC to PC in an in vitro system [50].