CDK5RAP2 and Primary microcephaly: Primary microcephaly, also known as true microcephaly or autosomal recessive primary microcephaly, is mainly caused by genes that regulate the assembly of centrosomes and cilium caused by autosomal recessive mutations including MCPH1, ASPM, WDR62, CDK5RAP2, CPAP, and CENPJ. Currently, specific congenital microcephaly brain organoids carrying mutations of CDK5RAP2, CPAP, ASPM, and WDR62 have been established, respectively (Lancaster et al., 2013; Li et al., 2017; Quadrato and Arlotta, 2017; Zhang et al., 2019).