DSG1 and Platelet storage pool disease: In addition to the presence of four desmosomal Dsg isoforms, i.e. Dsg1‐4, Dsc1, 2 and 3, all of which are derived from different genes, Dsc1 has been previously identified as the target antigen of IgA autoantibodies in the subcorneal pustular dermatosis (SPD)‐type of intercellular IgA dermatosis.