Trisomy 13

**Semantic type:** Cell or Molecular Dysfunction

**Definition:** A chromosomal abnormality characterized by the presence of three copies of genetic material for chromosome 13, instead of the normal two. It leads to a variety of abnormalities that include mental retardation, microcephaly, low-set ears, eye structural defects, polydactyly, and limb abnormalities.

**Synonyms:** - Trisomy-13