The t(4;14) translocation leads to the simultaneous overexpression of two genes, FGFR3 and MMSET. FGFR3 has transforming activity in vitro and in vivo, but approximately 30% of t(4;14) MM patients do not express FGFR3, whereas overexpression of MMSET isoforms is a universal feature of t(4;14) cases [5-7]. Here, FGFR3 is linked to Miyoshi myopathy.