The PI3K/Akt/mTOR signaling cascade has been implicated in the pathogenesis of various neurodegenerative and neuropsychiatric disorders, e.g., Alzheimer’s disease [24], Parkinson’s disease [25], epilepsy [26], tuberous sclerosis complex (TSC) [11], fragile X syndrome [10], depression [27], schizophrenia [28] and bipolar disorder [29]. The gene discussed is AKT1; the disease is fragile X syndrome.