In contrast to the reported human phenotype, the Hertwig’s anemia mice (exon 4 inversion of the Cdk5rap2 gene, deletion of a large part of the γ-tubulin ring complex (γTuRC) binding domain) not only have microcephaly, but also a hematopoietic phenotype (hypoproliferative anemia, leucopenia, predisposition to hematopoietic tumors) and defects in multiple organs [6]. Here, CDK5RAP2 is linked to microcephaly.