As an example of interrogating target validity in established and emerging AD models, one could use neurons derived from human induced pluripotent stem cells (iPSC) that harbor an AD‐relevant mutation, such as a line carrying the point mutation in the Presenilin 1 gene known to cause familial AD, and isogenic control iPSC as an AD‐relevant system. The gene discussed is PSEN1; the disease is Alzheimer disease.