BCMA is encoded by a 2.92-kb TNFRSF17 gene located on the short arm of chromosome 16 (16p13.13) and composed of 3 exons separated by 2 introns. BCMA is a 184 amino acid and 20.2-kDa type III transmembrane glycoprotein, with the extracellular N terminus containing a conserved motif of 6 cysteines. BCMA was found to be a member of tumor necrosis factor (TNF) receptor (TNFR) superfamily. There are four natural splice variants of human BCMA that present with different receptor binding affinities, membrane-anchoring ability, and intracellular domain signaling.