A trisomy occurs when the cells of the body contain an extra chromosome. This can lead to health issues including birth defects and intellectual disability.
The sex chromosomes determine whether the baby will be male (XY) or female (XX). Sometimes there may be too many or too few sex chromosomes, resulting in potential health issues.
A microdeletion occurs when a tiny piece of a chromosome is missing, or deleted. This deletion can result in birth defects or intellectual disability.