Black et al. (2016) reported that endogenous BAM transcription factors expression could be engineered using the CRISPR/Cas9 system to convert fibroblasts into neuronal cells. Small molecule cocktails have also been reported to directly induce neurons. By adding a cocktail of seven small chemicals that regulate neuronal transcription factor expression, Hu et al. (2015) converted fibroblasts from patients with fAD carrying APP or PS1 mutations into neuronal cells, and observed amyloid and tau phenotypes, showing the promising potential of using iNs to model AD. Here, PSEN1 is linked to Alzheimer disease.