Finally, HZD regions observed in <5% of cases have relevance in MM biology due to involvement in important signaling pathways, such as NF-κB (CYLD, BIRC2, and BIRC3), regulation of cell cycle (CDKN1B, RB1), or connection with apoptosis (WWOX, FAF1) [33, 34]. Here, RB1 is linked to Miyoshi myopathy.