What are the different types of chromosomal aberrations?

The most common type of numerical chromosomal abnormality is aneuploidy, which involves an abnormal number of chromosomes due to either an extra or missing chromosome. 

Types of structural abnormalities include: 

• Duplications: presence of extra copies of chromosome segments
• Deletions: loss of chromosome segments
• Translocations: exchange of genetic material between non-homologous chromosomes
• Inversions: reversal of chromosome segments
• Isochromosomes: chromosomes with identical arms due to unequal splitting
• Ring chromosomes: formation of circular chromosomes due to deletions and reconnections