Defects in the microcephalin (MCPH1) gene or its binding partner, SET, nuclear oncogene, promote precocious chromosomal condensation, which is thought to be the key defect leading to microencephaly (reduction in human brain size); in cell culture, simultaneous knockdown of condensin II and SET alleviated the precocious chromosomal condensation defect [3]. This evidence concerns the gene SET and microcephaly.