Representative microphotographs of transverse cryosections from the specimens of patient III-2 in family 1. (A–D) Note the perinuclear and subsarcolemmal aggregation of fused in sarcoma/translated in liposarcoma (FUS/TLS) with sparse staining in cytoplasm (arrows), whereas FUS/TLS mislocalization was scarcely observed. (E–H) In atrophic fibers (asterisks), diffuse cytoplasmic expression and extranuclear/subsarcolemmal aggregation of TATA-binding protein–associated factor 2N (TAF15) were frequently found. The aggregation is partially colabeled with ubiquitin (arrowheads). (I–L) In addition to heterogeneous nuclear ribonucleoprotein (hnRNP) A1 and A2B1, Ewing sarcoma breakpoint region 1 (EWSR1) and sequestome-1/p62 (SQSTM1/p62) double-positive aggregation was observed in rimmed vacuoles (arrows). (M–P) Note the multisystem proteinopathy 1–linked valosin-containing protein (VCP)/p97, SQSTM1/p62, and hnRNPA1 triple-labeled aggregates in the rimmed vacuoles (arrows). (Q–T) In atrophic fibers, amyotrophic lateral sclerosis/distal myopathy–linked matrin-3 was aberrantly involved in the subsarcolemmal SQSTM1/p62-positive aggregates (arrowheads). Scale bars = 50 μm.