 Hypothesis: It is proposed that part of the pathophysiology of the central nervous system in the animal model of the fragile X syndrome may be determined by oxidative stress. In addition, Fragile X patients showed a significantly low level of ascorbic acid in plasma. The biochemical characteristics of oxidative stress may be reversed in the FMR1-KO mice, by a chronic treatment with antioxidant compounds such as tocopherol or melatonin, it may also normalize several hallmarks of the Syndrome such as hyperactivity, anxiety and cognitive deficits. The normalization of the oxidative stress is proposed as a new therapeutic pathway to alleviate conditions caused by an excess of free radicals that are crucial in neurodevelopmental diseases such as autism, down syndrome and other diseases of the central nervous system. 