FMR1 and fragile X syndrome: The lack of FMRP due to mutations in its encoding gene FMR1 can cause fragile X syndrome, the most common form of inherited mental retardation and autism spectrum disorders (Bear et al., 2004; Garber et al., 2006; Bassell and Warren, 2008; Rooms and Kooy, 2011; Bhakar et al., 2012; Wang et al., 2012b).