Complete Trisomy 21 Syndrome

**Semantic type:** Disease or Syndrome

**Definition:** A syndrome characterized by the presence of three complete copies of genetic material for chromosome 21, instead of the normal two. It leads to a variety of abnormalities that include mental retardation, macroglossia, microgenia, epicanthic eyelids, and a single transverse palmar crease.

**Synonyms:** - Down Syndrome