Cyclin-dependent kinase 6 (p40cdk6 also known as PLSTIRE) belongs to a family of proteins designated as cdks. They are critical regulators of cell cycle progression. The prototype member of this family, p34cdc2, and a related protein cdk2, function late in the cycle while cdk4 and cdk6 are critically involved in G1 to S progression. CDK6 is essential for cell proliferation within the dentate gyrus of the hippocampus and the cuventricular zone of the lateral ventricles. Mutations in the gene results in microcephaly 12, primary, autosomal recessive (MCPH12).