CYFIP1 and fragile X syndrome: Subject HI2172 possessed a non-synonymous, missense mutation of the CYFIP1 (cytoplasmic FMRP-interacting protein 1) gene located on chromosome 15 which encodes a protein that interacts with the familial mental retardation protein (FMRP) that when disturbed, causes the fragile X syndrome by impacting on development and maintenance of neuronal structures [108,109].