For example, the KIF11 gene, which likely plays a role in retinal vascular development,43 is strongly expressed in proliferating embryonic tissues including the brain, the spinal cord, and a proliferative region at the periphery of the retina.44 Furthermore, additional genes associated with microcephaly such as the COH1 gene, the NBS1 gene, and the CDK19 gene are all expressed in the human brain and retina.45, –, 47. The gene discussed is CDK19; the disease is microcephaly.