Tip60 cKO mice showed microcephaly, and NSCs derived from Tip60 cKO brains showed a proliferation defect in in vivo and in vitro accumulation of M phase cells in vivo, indicating that the dysregulation of cell growth in Tip60-deficient NSCs contributes to the occurrence of microcephaly in the Tip60 cKO brain. Here, KAT5 is linked to microcephaly.