Neither SMPX-positive protein inclusions, nor other SMPX accumulation was observed in any other disease control myopathies with rimmed vacuolar and/or myofibrillar pathology (2 × HMERF, 2 × sIBM, 1 × LGMD1D, 1 × WDM, and 1 × MFM with unknown etiology, data not shown). Here, SMPX is linked to myopathy.