One clue regarding this issue comes from our recent quantitative single‐cell time‐lapse analysis of neuronal differentiation and migration using Reln‐del iPSC revealing the developmental significance of reelin in migrating directionality.25 To examine directional abnormality in neuronal migration observed in human RELN‐deleted iPSC in vivo, we generated a mouse line in the C57BL/6J strain harboring the specific Reln deletion identified by us in a Japanese subject with schizophrenia, and named the line Reln‐del mice. This evidence concerns the gene RELN and schizophrenia.