A chromosome aberration is a deviation from the norm. It is a mutation at the chromosomal level that can be structural or numerical.
Numerical aberrations include euploidies (the entire set of chromosomes is duplicated once or several times) or aneuploidies, where the numerical aberration involves only one chromosome. Examples of numerical chromosome aberrations include:
- Down syndrome (trisomy of chromosome 21),
- Edwards syndrome (trisomy of chromosome 18)
- Patau’s syndrome (trisomy of chromosome 13)
