G3BP1 and distal myopathy, Welander type: In analogy to Welander distal myopathy, impairment of stress granule formation is proposed as a possible pathogenic mechanism for VCPDM, since cytoplasmic granules containing stress granule components, TIA1 cytotoxic granule-associated RNA binding protein (TIA1) and G3BP stress granule assembly factor 1 (G3BP1), are observed in muscular samples by Palmio et al. (5), and p.S85C-mutated matrin-3 reduces cellular stress response in vitro (18).