Loss of Heterozygosity

**Semantic type:** Cell or Molecular Dysfunction

**Definition:** A genetic variation where gain, loss, or exchange of DNA results in monoallelic loss of function mutations in a diploid cell. In the context of tumor suppressor genes, where a single copy is sufficient for functionality, loss of function for the second allele is associated with tumorigenesis.

**Synonyms:** - LOH - LOH - loss of heterozygosity