CDK5RAP2 and microcephalic primordial dwarfism: This is consistent with studies that showed only a minor reduction in γ-tubulin signal at centrosomes in CDK5RAP2 knockout cells62,63 and that homozygous mutations in the CDK5RAP2-encoding gene in humans are not lethal, though they cause developmental disorders such as microcephaly and Seckel syndrome, probably due to perturbations of cell division64,65.