Centric heterochromatin refers to the condensed, darkly-staining region of DNA located near the center of a chromosome. It is distinct from the lighter-staining euchromatin, which contains most of the genes responsible for protein synthesis. Synonyms for centric heterochromatin include constitutive heterochromatin, pericentromeric heterochromatin, and repeat-rich regions. These regions of DNA are typically comprised of repetitive sequences, some of which are transposable elements or satellite DNA. Centric heterochromatin is important for maintaining chromosome structure and function, as well as regulating gene expression. Dysregulation of this process can lead to disease, such as certain types of cancer.