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.
Immunodeficiency: Therapies include thymus transplantation and adoptive transfer of mature T cells (ATMTC) for individuals with complete DiGeorge syndrome and appropriate prophylaxis measures and monitoring autoimmune complications for incomplete or partial DiGeorge syndrome.
A different siderotic scenario of locoregional character,2 is caused by mutations that affect cell iron utilization and result in intracellular foci of siderosis that damages cells of organs such as brain, heart, endocrine glands, or bone marrow (Figure), 6 and ensuing dysfunctions.