Chromosomal aberrations are substantial changes in chromosome structure that occur in two primary ways: 1) altering the total genetic information by increasing or decreasing it through duplications or deletions, and 2) rearranging the genetic material through inversions or translocations while keeping the total amount the same. Specific types of aberrations include deletions where parts of chromosomes are missing, duplications where segments are repeated, inversions where segments flip orientation, and translocations where segments are transferred between non-homologous chromosomes. These structural changes can cause genetic disorders and impact phenotypes.