The FMRP protein, which is involved in RNA regulation, plays a crucial role in neuronal development, synaptic plasticity, and dendritic spine architecture [159], and recent studies on FXS-patient-derived neural progenitor cells (NPCs) have indeed revealed abnormal gene expressions related to protein synthesis, neural development, and migration [160,161,162,163]. The gene discussed is FMR1; the disease is fragile X syndrome.