I hope, this will help)
Polyploidy represents the case of chromosomal mutation, where the cell contains the extra set of chromosomes: three sets – triploid, four sets – tetraploid, etc. As a rule, this kind of mutation is inherit to plants.
Aneuploidy is also a chromosomal mutation, but the difference is that the cell contains the abnornal number of chromosomes – extra or fewer chomosomes. The most common cases of aneuploidy in humans include Down syndrome, Patau syndrome, and Adwards syndrome (all of them are trisomies).