FMR1 and fragile X syndrome: As previously reported, FXS patients (Ferri et al., 1994; Miller et al., 1999) and mice (Musumeci et al., 2000) show anomalous reaction to sensory stimuli and our experiments confirm the hyper-reaction of Fmr1 KO mice to loud acoustic stimulus (~122 dB), given using a doorbell mounted inside the experimental cage.