X5L, or Family with sequence similarity 50 member B, is a human gene encoded by FAM50B. It may also be known as: Protein FAM50B; Protein XAP-5-like; D6S2654E; family with sequence similarity 50, member B. The encoded protein has an amino acid length of 325 and a mass of 38.7 kDa. X5L is a member of the FAM50 family. Homologs of this gene exist in other organisms, including: Mouse, Rat.