FAM200B (Family with sequence similarity 200 member B), is a protein which in humans is encoded by the FAM200B gene.The gene encodes a 657 amino acid protein. The FAM200B protein is a large intracellular protein with no well defined functional domains. Structural data states there is no experimentally proven structures available, however predicted tertiary structures are available. Expression data states FAM200B is expressed moderately and ubiquitously in all tissues, with relatively higher expression in the brain and thymus. Although its function remains unknown, predicted nuclear localization and expression patterns suggest that FAM200B may be involved in regulatory processes such as gene expression or protein protein interactions.