MAFB and Miyoshi myopathy: In MM, the overexpression of large MAF (v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog proto-oncogene) genes, including MAF, MAFB, and MAFA, characterized by chromosomal translocations into immunoglobulin heavy chain (IGH) loci [3–6], have been associated with poor prognosis [7, 8].