KCNN4 and cardiac arrhythmia: However it remains to be clarified (i) how NDPK-B expression was upregulated based on the desmosomal gene mutation occurring in ARVC, (ii) whether the observed changes in NDPK-B and SK4 are general in all ARVC patients with different gene mutations and (iii) why application of NDPK-B into a cell caused different forms of arrhythmias.