Loss of heterozygosity, often abbreviated as LOH, refers to the loss of genetic diversity in a population due to the loss of one or more alleles. It occurs when a mutation or deletion affects a region of the genome that carries a gene or genes associated with a particular trait. Some synonyms for LOH include allelic imbalance, gene deletion, gene silencing, gene conversion, and genomic instability. These terms are often used interchangeably to describe the same phenomenon, which contributes to the development of many genetic disorders, including cancer. Understanding the mechanisms of LOH is critical for developing effective therapies for these diseases.