ABCB1 and fragile X syndrome: These genes include ATP Binding Cassette Subfamily B Member 1 (ABCB1) and Thrombospondin-1 (THBS1), as well as the fragile X messenger ribonucleoprotein 1 (FMR1) gene in Fragile X Syndrome to induce transcriptional repression (Harikrishnan et al., 2005).