Aneuploidy refers to the presence of extra or missing copies of specific chromosomes. The presence of one extra copy of a chromosome is referred to as trisomy. The absence of one copy of a chromosome is called monosomy. According to the given information, the fetus has 45 chromosomes while the humans have a total of 46 chromosomes. This means that the fetus was monosomic (aneuploid) for a chromosome.
