Different cases in which chromosomes obtained from short-term lymphocyte cultures appear with separated centromeres are reviewed. These include: (1) C-anaphases in the colchicine-resistance mutation, (2) C-anaphases as a common variant, (3) premature centromere division (PCD) in elderly women, (4) PCD in Alzheimer's disease, (5) early splitting and puffing of centromeres in Roberts' syndrome.