The primary fusion genes identified in EMC are EWSR1::NR4A3 and TATA-box binding protein-associated factor 15::nuclear receptor subfamily 4 group A member 3 (TAF15::NR4A3) gene fusions (Hisaoka and Hashimoto 2005), whereas PPMS is characterized by the EWSR1::CREB1 gene fusion. Here, CREB1 is linked to primary progressive multiple sclerosis.