Rett syndrome is a devastating neurodevelopmental disorder, and a recent study reported that induced pluripotent stem (iPS) cell-derived neural progenitor cells (NPCs) from patients with Rett syndrome exhibit aberrant up-regulation of LIN28A and lower glia-to-neuron ratio upon differentiation (Kim et al., 2019). The gene discussed is LIN28A; the disease is atypical Rett syndrome.