Final answer:
An isochromosome is characterized by the deletion of one arm and the mirror image duplication of the other arm, leading to two identical arms and potential genetic disorders.
Step-by-step explanation:
The term used for a chromosome in which one arm is deleted and the other arm is duplicated in a mirror image fashion is an isochromosome. In this chromosomal anomaly, one arm of the chromosome is lost and the other arm is duplicated, including the centromere, resulting in a chromosome with two identical arms. This can lead to genetic disorders due to the alteration in the normal balance of gene dosage.