Aneuploidy is a chromosomal imbalance of one or a few chromosomes aboe or below the normal human chromosomal number of 46, which may lead a child to hae abnormalities including Down Syndrome.

• 非整倍性是指个体的染色体不均衡或者或者某些染色体比正常人的染色体数目多或者少包括唐氏综合症。