Multimerization and acquisition of protease-resistance often go hand-in-hand for prion diseases and here we note the HRdup PrP holoprotein has different assembly properties than M128V PrP (Fig 3) and that a self-aggregation determinant [74] lies within the boundaries of the 16 kDa species defined by epitope mapping. The gene discussed is PRNP; the disease is prion disease.