PNN and ankylosis: The increased expression of desmosomal cadherins, desmoglein 2 (DSG2) and desmocollin 2 (DSC2), and the cytoplasmic desmosome-associated protein, plakophilin 1 (PKP1), are likewise consistent with human ERM.32 Collectively, the results suggest that there is a change in the ERM state during ankylosis, which may be associated with an increased inflammatory response.