What are structural chromosome abnormalities?
Structural chromosome abnormalities occur when there is a change in the structure or components of a chromosome. The total number of chromosomes is usually normal (46 total per cell). Structural chromosome abnormalities occur when part of a chromosome is missing, a part of a chromosome is extra, or a part has switched places with another part. Ultimately, this leads to having too much or too little genetic material, which is a cause of some birth defects. Each chromosome has many segments which are usually divided into a “short arm” and a “long arm” of the chromosome. The short arm which is the upper half of the chromosome, is known as the “p arm” and the long arm, which is the lower half of the chromosome, is the “q arm.” The centromere is the center part of a chromosome that appears “pinched” between the p and q arms.
