FCRL5 and Miyoshi myopathy: Other antigens under development as potential targets in MM include GPRC5D, a transmembrane orphan receptor of the G protein-coupled receptor family [81], FcRH5, a membrane protein, which regulates B-cell receptor signaling [82], and CD38, a member of the ADP-ribosyl cyclase family, which is involved in the regulation of calcium homeostasis, signaling and adhesion [83].