Although dysregulation of Semaphorins in epileptic humans has not yet been reported, the mRNA encoding Sema3F is a target of the fragile X mental retardation protein (FMRP) and is decreased in polysomes from fragile X syndrome patients’ cells, suggesting that Sema3F is downregulated in these patients (Darnell et al., 2001). The gene discussed is SEMA3F; the disease is fragile X syndrome.