The pIBM group as a whole showed a high %FS for LC3 (median, 16.8%FS) and a low %FS for TDP-43 (median, 1.2%FS), consistent with the idea that the majority of pIBM cases represent an early stage of IBM with incompletely developed pathologic features. The gene discussed is TARDBP; the disease is inclusion body myositis.