Definition is a rhetorical mode that can be used in something smaller or shorter than a full paper. You can use extended definition for several paragraphs only in a paper of much greater length. You also can add to a paper a one-paragraph definition--like a brief encyclopedia definition.
The research group, headed by Dr. Lukas Sommer at the Swiss Federal Institute of Technology, has identified a heretofore unknown role for the TGF cell-to-cell signaling pathway in the pathogenesis of DiGeorge syndrome.
1 injury to or removal of the parathyroid glands. 2  DiGeorge syndrome, which is a genetic disorder that affects development of certain body systems. 3  genetics. 4  autoimmune disease. 5  cancer radiation treatments.  low magnesium levels.