All relevant articles were identified and were systematically searched through the PubMed, Medical Literature Analysis and Retrieval System Online (MEDLINE) database, and UpToDate till June 2022 by using the following Medical Subject Headings (MESH) words: Acute phase reactants, autoimmune diseases, biomarker, cardiovascular diseases, cancer, c-reactive protein, cerebrovascular diseases, high sensitivity c-reactive protein, diabetes mellitus, inflammation, obstructive sleep apnea, and stroke. This evidence concerns the gene CRP and obstructive sleep apnea syndrome.