Biology Ease Staff asked 2 years ago
Chromosomal abnormalities are the most common birth defects, occurring in approximately 5% of all pregnancies. Most chromosome abnormalities are inherited and occur when an error occurs during cell division, resulting in an extra or missing chromosome.
The most common chromosome abnormality is Down’s syndrome (trisomy 21). It affects about 1 in 700 live births and occurs when there is an extra copy of the 23rd chromosome. This results in a range of physical and mental effects that can include:
- Delayed development, including poor muscle tone and poor muscle control;
- Microcephaly (small head size);
- Short stature;
- Heart problems;
- Disability; and
- Learning difficulties.