Trisomy
| Trisomy | |
|---|---|
| Example of trisomy 21 (Down syndrome) detected via qPCR short tandem repeat analysis | |
| Specialty | Medical genetics | 
A trisomy is a type of polysomy in which there are three instances of a particular chromosome, instead of the normal two. A trisomy is a type of aneuploidy (an abnormal number of chromosomes).