Aneuploidy is due to:

A i.e. Non disjunction at meiosis- Aneuploidy is a condition in which a cell contains other than haploid number of chromosomes or an exact multiple of it. It produced by non- disjunction of chromosomes at meiosisQ and is common in cancer cells.Term 'Ploid is used to refer number of chromosomes in cells. Euploid: Normal resting diploid cell. Tetraploid: Cells just before division.